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数学初二计算题及答案,八年级计算机考试知识点

  • 数学
  • 2024-04-14

数学初二计算题及答案?4、(6a^3b-9a^c)÷3a^2 5、(5ax^2+15x)÷5x 6、(a+2b)(a-2b)7、(3a+b)^2 8、(1/2 a-1/3 b)^2 9、(x+5y)(x-7y)10、(2a+3b)(2a+3b)11、(x+5)(x-7)12、5x^3×8x^2 13、那么,数学初二计算题及答案?一起来了解一下吧。

初二上必刷计算题及答案

(1)99²-2.99²

(2)80×3.5²+160×3.5×1.5+80×1.5²

(3)181²-61²÷301²-181²

(4)5x-5y+5z

(5)-5a²+25a-5a

(6)2a(b+c)-3(b+c)

(7)(ab+a)+(b+1)

(8)-4m³+16m³-28m

(9)16x-25x³y²

(10)36m²a-9m²a²-36m²

√32-3√1/2+√2

√12+√27/√3-√1/3×√12

√50+√30/√8-4

(√6-2√15)×√3-6√1/2

√2/3-4√216+43√1/6

√8+√30-√2

√40-5√1/10+√10

√2+√8/√2

√2/9+√50+√32

(1-√3)(√3+2)

(√8+3√6)÷√2-√3×√0.7

(-3+√6)(-3-√6)-(√3-1/√3)²

³√0.125-√3

1/16+³√(1-7/8)²

√2/3-√216+42√1/6

解方程√3

X-1=√2

X

求X

{√5

X-3√

Y=1}

{√3

X-√5

Y=2}

注:X全部不在根号内

√(1/2x)^2+10/9x^2

=√[1/(4x^2)+10/(9x^2)]

=√49/36x^2

若x>0,=7/(6x)

若x<0,=-7/(6x)

√a^4mb^2n+1

=√(a^2mb^n)^2+1

=a^2mb^n+1

√(4a^5+8a^4)(a^2+3a+2)

=√[4a^4(a+2)][(a+2)(a+1)]

=√[4a^4(a+2)^2(a+1)]

=2a^2(a+2)√(a+1)

.

3√(1/6)-4√(50)+30√(2/3)

答案3√(1/6)-4√(50)+30√(2/3)

=

3×√6/6-4×5√2+30×√6/3

=√6/2-20√2+10√6

2.

(1-根号2)/2乘以(1+根号2)/2

题是这样的二分之一减根号2乘以二分之一加根号2

答案:(1-根号2)/2乘以(1+根号2)/2

=(1-√2)*(1-√2)/4

=(1-2)/4

=-1/4

1.3√(1/6)-4√(50)+30√(2/3)

答案3√(1/6)-4√(50)+30√(2/3)

=

3×√6/6-4×5√2+30×√6/3

=√6/2-20√2+10√6

2.

(1-根号2)/2乘以(1+根号2)/2

题是这样的二分之一减根号2乘以二分之一加根号2

答案:(1-根号2)/2乘以(1+根号2)/2

=(1-√2)*(1-√2)/4

=(1-2)/4

=-1/4

3.√(1/2x)^2+10/9x^2

√[(1/2x)^2+10/9x^2]

=√(x^2/4+10x^2/9)

=√(9x^2/36+40x^2/36)

=√(49x^2/36)

=7x/6;

4.√a^4mb^2n+1(a、b为正数)

[√(a^4mb^2n)]+1(a、b为正数)

=a^2mb^n+1;

5.√(4a^5+8a^4)(a^2+3a+2)(a>=0)

√[(4a^5+8a^4)(a^2+3a+2)](a>=0)

=√[4a^4(a+2)(a+2)(a+1)]

=√[(2a^2)^2(a+2)^2(a+1)]

=2a^2(a+2)√(a+1).

太多了呀,只能这样了,我还有事

您好!

①5√8-2√32+√50

=5*3√2-2*4√2+5√2

=√2(15-8+5)

=12√2

②√6-√3/2-√2/3

=√6-√6/2-√6/3

=√6/6

③(√45+√27)-(√4/3+√125)

=(3√5+3√3)-(2√3/3+5√5)

=-2√5+7√5/3

④(√4a-√50b)-2(√b/2+√9a)

=(2√a-5√2b)-2(√2b/2+3√a)

=-4√a-6√2b

⑤√4x*(√3x/2-√x/6)

=2√x(√6x/2-√6x/6)

=2√x*(√6x/3)

=2/3*x*√6

⑥(x√y-y√x)÷√xy

=x√y÷√xy-y√x÷√xy

=√x-√y

⑦(3√7+2√3)(2√3-3√7)

=(2√3)^2-(3√7)^2

=12-63

=-51

⑧(√32-3√3)(4√2+√27)

=(4√2-3√3)(4√2+3√3)

=(4√2)^2-(3√3)^2

=32-27

=5

⑨(3√6-√4)²

=(3√6)^2-2*3√6*√4+(√4)^2

=54-12√6+4

=58-12√6

⑩(1+√2-√3)(1-√2+√3)

=[1+(√2-√3)][1-(√2-√3)]

=1-(√2-√3)^2

=1-(2+3+2√6)

=-4-2√6

1.

=5√5

-

1/25√5

-

4/5√5

=√5*(5-1/25-4/5)

=24/5√5

2.=√144+576

=√720

=12√5

3.)√(8/13)^2-(2/13)^2

=

√(8/13+2/13)(8/13-2/13)

=(2/13)√15

初二计算题训练100道

(1)66x+17y=3967

25x+y=1200

答案:x=48 y=47

(2) 18x+23y=2303

74x-y=1998

答案:x=27 y=79

(3) 44x+90y=7796

44x+y=3476

答案:x=79 y=48

(4) 76x-66y=4082

30x-y=2940

答案:x=98 y=51

(5) 67x+54y=8546

71x-y=5680

答案:x=80 y=59

(6) 42x-95y=-1410

21x-y=1575

答案:x=75 y=48

定义

加法:把两个数合并成一个数的运算。

减法:在已知两个加数的和与其中的一个加数,求另一个加数的运算。

乘法:求两个数乘积的运算。

一个数乘整数,是求几个相同加数和的简便运算。

除法:已知两个因数的积与其中的一个因数,求另一个因数的运算。

以上内容参考:百度百科-四则运算

初二计算题200题带答案

①5√8-2√32+√50

=5*3√2-2*4√2+5√2

=√2(15-8+5)

=12√2

②√6-√3/2-√2/3

=√6-√6/2-√6/3

=√6/6

③(√45+√27)-(√4/3+√125)

=(3√5+3√3)-(2√3/3+5√5)

=-2√5+7√5/3

④(√4a-√50b)-2(√b/2+√9a)

=(2√a-5√2b)-2(√2b/2+3√a)

=-4√a-6√2b

⑤√4x*(√3x/2-√x/6)

=2√x(√6x/2-√6x/6)

=2√x*(√6x/3)

=2/3*|x|*√6

⑥(x√y-y√x)÷√xy

=x√y÷√xy-y√x÷√xy

=√x-√y

⑦(3√7+2√3)(2√3-3√7)

=(2√3)^2-(3√7)^2

=12-63

=-51

⑧(√32-3√3)(4√2+√27)

=(4√2-3√3)(4√2+3√3)

=(4√2)^2-(3√3)^2

=32-27

=5

⑨(3√6-√4)?

=(3√6)^2-2*3√6*√4+(√4)^2

=54-12√6+4

=58-12√6

⑩(1+√2-√3)(1-√2+√3)

=[1+(√2-√3)][1-(√2-√3)]

=1-(√2-√3)^2

=1-(2+3+2√6)

=-4-2√6

(1)5√12×√18

=5*2√3*3√2

=30√6;

(2)-6√45×(-4√48)

=6*3√5*4*4√3

=288√15;

(3)√(12a)×√(3a) /4

=√(36a^2)/4

=6a/4

=3a/2.

5.

x^2(y+z)^2-2xy(x-z)(y+z)+y^2(x-z)^2

=[x(y+z)-y(x-z)]^2

=(xz+yz)^2

=z^2(x+y)^2

6.

3(a+2)^2+28(a+2)-20

=[3(a+2)-2][(a+2)+10]

=(3a+4)(a+12)

7.

(a+b)^2-(b-c)^2+a^2-c^2

=(a+b)^2-c^2+a^2-(b-c)^2

=(a+b+c)(a+b-c)+(a+b-c)(a-b+c)

=(a+b-c)(a+b+c+a-b+c)

=2(a+b-c)(a+c)

8.

x(x+1)(x^2+x-1)-2

=(x^2+x)(x^2+x-1)-2

=(x^2+x)^2-(x^2+x)-2

=(x^2+x-2)(x^2+x+1)

=(x+2)(x-1)(x^2+x+1)

9.

9x^2(x-1)^2-3(x^2-x)-56

=9x^2(x-1)^2-3x(x-1)-56

=[3x(x-1)-8][3x(x-1)+7]

=(3x^2-3x-8)(3x^2-3x+7)

有理数练习

练习一(B级)

(一)计算题:

(1)23+(-73) (2)(-84)+(-49) (3)7+(-2.04) (4)4.23+(-7.57) (5)(-7/3)+(-7/6) (6)9/4+(-3/2) (7)3.75+(2.25)+5/4 (8)-3.75+(+5/4)+(-1.5)

5.

x^2(y+z)^2-2xy(x-z)(y+z)+y^2(x-z)^2

=[x(y+z)-y(x-z)]^2

=(xz+yz)^2

=z^2(x+y)^2

6.

3(a+2)^2+28(a+2)-20

=[3(a+2)-2][(a+2)+10]

=(3a+4)(a+12)

7.

(a+b)^2-(b-c)^2+a^2-c^2

=(a+b)^2-c^2+a^2-(b-c)^2

=(a+b+c)(a+b-c)+(a+b-c)(a-b+c)

=(a+b-c)(a+b+c+a-b+c)

=2(a+b-c)(a+c)

8.

x(x+1)(x^2+x-1)-2

=(x^2+x)(x^2+x-1)-2

=(x^2+x)^2-(x^2+x)-2

=(x^2+x-2)(x^2+x+1)

=(x+2)(x-1)(x^2+x+1)

9.

9x^2(x-1)^2-3(x^2-x)-56

=9x^2(x-1)^2-3x(x-1)-56

=[3x(x-1)-8][3x(x-1)+7]

=(3x^2-3x-8)(3x^2-3x+7)

1.125*3+125*5+25*3+25

2.9999*3+101*11*(101-92)

3.(23/4-3/4)*(3*6+2)

4. 3/7 × 49/9 - 4/3

5. 8/9 × 15/36 + 1/27

6. 12× 5/6 – 2/9 ×3

7. 8× 5/4 + 1/4

8. 6÷ 3/8 – 3/8 ÷6

9. 4/7 × 5/9 + 3/7 × 5/9

10. 5/2 -( 3/2 + 4/5 )

11. 7/8 + ( 1/8 + 1/9 )

12. 9 × 5/6 + 5/6

13. 3/4 × 8/9 - 1/3

14. 7 × 5/49 + 3/14

15. 6 ×( 1/2 + 2/3 )

16. 8 × 4/5 + 8 × 11/5

17. 31 × 5/6 – 5/6

18. 9/7 - ( 2/7 – 10/21 )

19. 5/9 × 18 – 14 × 2/7

20. 4/5 × 25/16 + 2/3 × 3/4

21. 14 × 8/7 – 5/6 × 12/15

22. 17/32 – 3/4 × 9/24

23. 3 × 2/9 + 1/3

24. 5/7 × 3/25 + 3/7

25. 3/14 ×× 2/3 + 1/6

26. 1/5 × 2/3 + 5/6

27. 9/22 + 1/11 ÷ 1/2

28. 5/3 × 11/5 + 4/3

29. 45 × 2/3 + 1/3 × 15

30. 7/19 + 12/19 × 5/6

31. 1/4 + 3/4 ÷ 2/3

32. 8/7 × 21/16 + 1/2

33. 101 × 1/5 – 1/5 × 21

34.50+160÷40

35.120-144÷18+35

36.347+45×2-4160÷52

37(58+37)÷(64-9×5)

38.95÷(64-45)

39.178-145÷5×6+42

40.812-700÷(9+31×11)

41.85+14×(14+208÷26)

43.120-36×4÷18+35

44.(58+37)÷(64-9×5)

45.(6.8-6.8×0.55)÷8.5

46.0.12× 4.8÷0.12×4.8

47.(3.2×1.5+2.5)÷1.6

48.6-1.6÷4= 5.38+7.85-5.37=

49.7.2÷0.8-1.2×5= 6-1.19×3-0.43=

50.6.5×(4.8-1.2×4)=

51.5.8×(3.87-0.13)+4.2×3.74

52.32.52-(6+9.728÷3.2)×2.5

53.[(7.1-5.6)×0.9-1.15] ÷2.5

54.5.4÷[2.6×(3.7-2.9)+0.62]

55.12×6÷(12-7.2)-6

56.12×6÷7.2-6

57.0.68×1.9+0.32×1.9

58.58+370)÷(64-45)

59.420+580-64×21÷28

60.136+6×(65-345÷23)

15-10.75×0.4-5.7

62.18.1+(3-0.299÷0.23)×1

63.(6.8-6.8×0.55)÷8.5

64.0.12× 4.8÷0.12×4.8

65.(3.2×1.5+2.5)÷1.6

66.3.2×6+(1.5+2.5)÷1.6

67.0.68×1.9+0.32×1.9

68.10.15-10.75×0.4-5.7

69.5.8×(3.87-0.13)+4.2×3.74

70.32.52-(6+9.728÷3.2)×2.5

71.[(7.1-5.6)×0.9-1.15] ÷2.5

72.5.4÷[2.6×(3.7-2.9)+0.62]

73.12×6÷(12-7.2)-6

74.12×6÷7.2-6

75.33.02-(148.4-90.85)÷2.5

1) 76.(25%-695%-12%)*36

77./4*3/5+3/4*2/5

78.1-1/4+8/9/7/9

79.+1/6/3/24+2/21

80./15*3/5

81.3/4/9/10-1/6

82./3+1/2)/5/6-1/3]/1/7

83./5+3/5/2+3/4

84.(2-2/3/1/2)]*2/5

85.+5268.32-2569

86.3+456-52*8

87.5%+6325

88./2+1/3+1/4

2) 89+456-78

3) 5%+. 3/7 × 49/9 - 4/3

4) 9 × 15/36 + 1/27

5) 2× 5/6 – 2/9 ×3

6) 3× 5/4 + 1/4

7) 94÷ 3/8 – 3/8 ÷6

8) 95/7 × 5/9 + 3/7 × 5/9

9) 6/2 -( 3/2 + 4/5 )

10) 8 + ( 1/8 + 1/9 )

11) 8 × 5/6 + 5/6

12) 1/4 × 8/9 - 1/3

13) 10 × 5/49 + 3/14

14) 1.5 ×( 1/2 + 2/3 )

15) 2/9 × 4/5 + 8 × 11/5

16) 3.1 × 5/6 – 5/6

17) 4/7 - ( 2/7 – 10/21 )

18) 19 × 18 – 14 × 2/7

19) 5 × 25/16 + 2/3 × 3/4

20) 4 × 8/7 – 5/6 × 12/15

21) 7/32 – 3/4 × 9/24

22) 1、 2/3÷1/2-1/4×2/5

2、 2-6/13÷9/26-2/3

3、 2/9+1/2÷4/5+3/8

4、 10÷5/9+1/6×4

5、 1/2×2/5+9/10÷9/20

6、 5/9×3/10+2/7÷2/5

7、 1/2+1/4×4/5-1/8

8、 3/4×5/7×4/3-1/2

9、 23-8/9×1/27÷1/27

10、 8×5/6+2/5÷4

11、 1/2+3/4×5/12×4/5

12、 8/9×3/4-3/8÷3/4

13、 5/8÷5/4+3/23÷9/11

23) 1.2×2.5+0.8×2.5

24) 8.9×1.25-0.9×1.25

25) 12.5×7.4×0.8

26) 9.9×6.4-(2.5+0.24)(27) 6.5×9.5+6.5×0.5

0.35×1.6+0.35×3.4

0.25×8.6×4

6.72-3.28-1.72

0.45+6.37+4.55

5.4+6.9×3-(25-2.5)2×41846-620-380

4.8×46+4.8×54

0.8+0.8×2.5

1.25×3.6×8×2.5-12.5×2.4

28×12.5-12.5×20

23.65-(3.07+3.65)

(4+0.4×0.25)8×7×1.25

1.65×99+1.65

27.85-(7.85+3.4)

48×1.25+50×1.25×0.2×8

7.8×9.9+0.78

(1010+309+4+681+6)×12

3×9146×782×6×854

5.15×7/8+6.1-0.60625

1. 3/7 × 49/9 - 4/3

2. 8/9 × 15/36 + 1/27

3. 12× 5/6 – 2/9 ×3

4. 8× 5/4 + 1/4

5. 6÷ 3/8 – 3/8 ÷6

6. 4/7 × 5/9 + 3/7 × 5/9

7. 5/2 -( 3/2 + 4/5 )

8. 7/8 + ( 1/8 + 1/9 )

9. 9 × 5/6 + 5/6

10. 3/4 × 8/9 - 1/3

11. 7 × 5/49 + 3/14

12. 6 ×( 1/2 + 2/3 )

13. 8 × 4/5 + 8 × 11/5

14. 31 × 5/6 – 5/6

15. 9/7 - ( 2/7 – 10/21 )

16. 5/9 × 18 – 14 × 2/7

17. 4/5 × 25/16 + 2/3 × 3/4

18. 14 × 8/7 – 5/6 × 12/15

19. 17/32 – 3/4 × 9/24

20. 3 × 2/9 + 1/3

21. 5/7 × 3/25 + 3/7

22. 3/14 ×× 2/3 + 1/6

23. 1/5 × 2/3 + 5/6

24. 9/22 + 1/11 ÷ 1/2

25. 5/3 × 11/5 + 4/3

26. 45 × 2/3 + 1/3 × 15

27. 7/19 + 12/19 × 5/6

28. 1/4 + 3/4 ÷ 2/3

29. 8/7 × 21/16 + 1/2

30. 101 × 1/5 – 1/5 × 21

31.50+160÷40 (58+370)÷(64-45)

32.120-144÷18+35

33.347+45×2-4160÷52

34(58+37)÷(64-9×5)

35.95÷(64-45)

36.178-145÷5×6+42 420+580-64×21÷28

37.812-700÷(9+31×11) (136+64)×(65-345÷23)

38.85+14×(14+208÷26)

39.(284+16)×(512-8208÷18)

40.120-36×4÷18+35

41.(58+37)÷(64-9×5)

42.(6.8-6.8×0.55)÷8.5

43.0.12× 4.8÷0.12×4.8

44.(3.2×1.5+2.5)÷1.6 (2)3.2×(1.5+2.5)÷1.6

45.6-1.6÷4= 5.38+7.85-5.37=

46.7.2÷0.8-1.2×5= 6-1.19×3-0.43=

47.6.5×(4.8-1.2×4)= 0.68×1.9+0.32×1.9

48.10.15-10.75×0.4-5.7

49.5.8×(3.87-0.13)+4.2×3.74

50.32.52-(6+9.728÷3.2)×2.5

51.[(7.1-5.6)×0.9-1.15] ÷2.5

52.5.4÷[2.6×(3.7-2.9)+0.62]

53.12×6÷(12-7.2)-6 (4)12×6÷7.2-6

102×4.5

7.8×6.9+2.2×6.9

5.6×0.25

8×(20-1.25)

1)127+352+73+44 (2)89+276+135+33

(1)25+71+75+29 +88 (2)243+89+111+57

9405-2940÷28×21

920-1680÷40÷7

690+47×52-398

148+3328÷64-75

360×24÷32+730

2100-94+48×54

51+(2304-2042)×23

4215+(4361-716)÷81

(247+18)×27÷25

36-720÷(360÷18)

1080÷(63-54)×80

(528+912)×5-6178

8528÷41×38-904

264+318-8280÷69

(174+209)×26- 9000

814-(278+322)÷15

1406+735×9÷45

3168-7828÷38+504

796-5040÷(630÷7)

285+(3000-372)÷36

1+5/6-19/12

3x(-9)+7x(-9

(-54)x1/6x(-1/3)

1.18.1+(3-0.299÷0.23)×1

2.(6.8-6.8×0.55)÷8.5

3.0.12× 4.8÷0.12×4.8

4.(3.2×1.5+2.5)÷1.6 (2)3.2×(1.5+2.5)÷1.6

5.6-1.6÷4= 5.38+7.85-5.37=

6.7.2÷0.8-1.2×5= 6-1.19×3-0.43=

7.6.5×(4.8-1.2×4)= 0.68×1.9+0.32×1.9

8.10.15-10.75×0.4-5.7

9.5.8×(3.87-0.13)+4.2×3.74

10.32.52-(6+9.728÷3.2)×2.5

11.[(7.1-5.6)×0.9-1.15] ÷2.5

12.5.4÷[2.6×(3.7-2.9)+0.62]

13.12×6÷(12-7.2)-6

14.12×6÷7.2-6

15.33.02-(148.4-90.85)÷2.5

7×(5/21+9/714)

a^3-2b^3+ab(2a-b)

=a^3+2a^2b-2b^3-ab^2

=a^2(a+2b)-b^2(2b+a)

=(a+2b)(a^2-b^2)

=(a+2b)(a+b)(a-b)

2.

(x^2+y^2)^2-4y(x^2+y^2)+4y^2

=(x^2+y^2-2y)^2

3.

(x^2+2x)^2+3(x^2+2x)+x^2+2x+3

=(x^2+2x)^2+4(x^2+2x)+3

=(x^2+2x+3)(x^2+2x+1)

=(x^2+2x+3)(x+1)^2

4.

(a+1)(a+2)+(2a+1)(a-2)-12

=a^2+3a+2+2a^2-3a-2-12

=3a^2-12

=3(a+2)(a-2)

5.

x^2(y+z)^2-2xy(x-z)(y+z)+y^2(x-z)^2

=[x(y+z)-y(x-z)]^2

=(xz+yz)^2

=z^2(x+y)^2

6.

3(a+2)^2+28(a+2)-20

=[3(a+2)-2][(a+2)+10]

=(3a+4)(a+12)

7.

(a+b)^2-(b-c)^2+a^2-c^2

=(a+b)^2-c^2+a^2-(b-c)^2

=(a+b+c)(a+b-c)+(a+b-c)(a-b+c)

=(a+b-c)(a+b+c+a-b+c)

=2(a+b-c)(a+c)

8.

x(x+1)(x^2+x-1)-2

=(x^2+x)(x^2+x-1)-2

=(x^2+x)^2-(x^2+x)-2

=(x^2+x-2)(x^2+x+1)

=(x+2)(x-1)(x^2+x+1)

写完一遍后再别这些题写一遍,以此类推,老师们看作业都是一看而过不会一个一个批的。

初二上册数学计算题及答案

【 #初中奥数#导语】奥林匹克数学竞赛或数学奥林匹克竞赛,简称奥数。奥数对青少年的脑力锻炼有着一定的作用,可以通过奥数对思维和逻辑进行锻炼,对学生起到的并不仅仅是数学方面的作用,通常比普通数学要深奥一些。下面是 无 为大家带来的初二年级奥数分式的运算试题及答案,欢迎大家阅读。

1.计算ax2byb2yax的结果是(B)

A.ax B.bxC.xbD.xa

2.计算-b2a?(-4a3b)?(-2a3b)的结果是(D)

A.-baB.ba

C.-b4aD.-4a9b

3.计算:

(1)2x3zy23y24xz2;

解:原式=6x3y2z4xy2z2=3x22z.

(2)x2-xyxy2?yy-x;

解:原式=x(x-y)xy2?yy-x

=-xy(x-y)xy2(x-y)

=-1y.

(3)x2-6x+9x2-1?x2+xx-3.

解:原式=(x-3)2(x+1)(x-1)?x(x+1)x-3

=x(x-3)x-1

=x2-3xx-1.

4.计算3ab÷b3a的结果是(D)

A.b2 B.18aC.9a D.9a2

5.化简2x2-1÷1x-1的结果是(A)

A.2x+1 B.2x

C.2x-1D.2(x+1)

6.计算:

(1)12x2y5z2÷4xy215z2;

解:原式=12x2y5z2?15z24xy2=9xy.

(2)a2-1a2+2a+1÷a2-aa+1;

解:原式=(a+1)(a-1)(a+1)2?a+1a(a-1)=1a.

(3)2x+6x2+2x÷(x+3).

解:原式=2(x+3)x2+2x?1x+3=2x2+2x.

7.由甲地到乙地的一条铁路全长为s km,火车的运行时间为a h;由甲地到乙地的公路全长为这条铁路全长的m倍,汽车全程运行b h.那么火车的速度是汽车速度的bam倍.

8.甲乙两个工程队合修一条公路,已知甲工程队每天修(a2-4)米,乙工程队每天修(a-2)2米(其中a>2),则甲工程队修900米所用时间是乙工程队修600米所用时间的多少倍?

解:900a2-4÷600(a-2)2=3a-62a+4.

答:甲工程队修900米所用时间是乙工程队修600米所用时间的3a-62a+4倍.

9.使代数式x+2x-3÷x+1x-2有意义的条件是(D)

A.x≠3且x≠2B.x≠3且x≠-1

C.x≠2且x≠-2D.x≠-1且x≠2且x≠3

10.已知分式x2-y2x乘以一个分式后结果为-(x-y)2x,则这个分式为-x-yx+y.

11.李明同学骑自行车上学用了a分钟,放学时沿原路返回家用了b分钟,则李明同学上学与回家的速度之比是ba.

12.计算:

(1)(a-2)?a2-4a2-4a+4;

解:原式=(a-2)?(a+2)(a-2)(a-2)2

=a+2.

(2)(a2+3a)÷a2-9a-3;

解:原式=a(a+3)?a-3(a+3)(a-3)

=a.

(3)x2-1x2-2x+1÷(x+1);

解:原式=(x+1)(x-1)(x-1)2?1x+1=1x-1.

(4)x2+2xy+y2xy-y2÷xy+y2x2-2xy+y2.

解:原式=(x+y)2y(x-y)?(x-y)2y(x+y)

=(x+y)(x-y)y2

=x2-y2y2.

13.先化简,再求值:a2-4a2+6a+9÷a-22a+6,其中a=-5.

解:原式=(a+2)(a-2)(a+3)2?2(a+3)a-2

=2(a+2)a+3=2a+4a+3.

当a=-5时,原式=2×(-5)+4-5+3=3.

14.有这样一道题:计算x2-2x+1x3-x÷x-1x2+x的值,其中x=2 017,某同学把x=2 017错抄成2 071,但他的计算结果正确,你说这是怎么回事?

解:原式=(x-1)2x(x+1)(x-1)?x(x+1)x-1=1.

计算的结果与x的值无关,

∴他的计算结果正确.

15.先化简:x+3x2-4x+4÷x2+3x(x-2)2,然后在不等式x≤2的非负整数解中选择一个适当的数代入求值.

解:原式=x+3x2-4x+4÷x2+3x(x-2)2

=x+3(x-2)2÷x(x+3)(x-2)2

=x+3(x-2)2?(x-2)2x(x+3)

=1x.

当x=1时,原式=1.

03综合题

16.有甲、乙两筐水果,甲筐水果重(x-1)2千克,乙筐水果重(x2-1)千克(其中x>1),售完后,两筐水果都卖了50元.

(1)哪筐水果的单价卖得低?

(2)高的单价是低的单价的多少倍?

解:(1)甲筐水果的单价为50(x-1)2,

乙筐水果的单价为50x2-1.

∵0

八上计算题120道及答案过程

①5√8-2√32+√50 =5*3√2-2*4√2+5√2 =√2(15-8+5) =12√2 ②√6-√3/2-√2/3 =√6-√6/2-√6/3 =√6/6 ③(√45+√27)-(√4/3+√125) =(3√5+3√3)-(2√3/3+5√5) =-2√5+7√5/3 ④(√4a-√50b)-2(√b/2+√9a) =(2√a-5√2b)-2(√2b/2+3√a) =-4√a-6√2b ⑤√4x*(√3x/2-√x/6) =2√x(√6x/2-√6x/6) =2√x*(√6x/3) =2/3*|x|*√6 ⑥(x√y-y√x)÷√xy =x√y÷√xy-y√x÷√xy =√x-√y ⑦(3√7+2√3)(2√3-3√7) =(2√3)^2-(3√7)^2 =12-63 =-51 ⑧(√32-3√3)(4√2+√27) =(4√2-3√3)(4√2+3√3) =(4√2)^2-(3√3)^2 =32-27 =5 ⑨(3√6-√4)? =(3√6)^2-2*3√6*√4+(√4)^2 =54-12√6+4 =58-12√6 ⑩(1+√2-√3)(1-√2+√3) =[1+(√2-√3)][1-(√2-√3)] =1-(√2-√3)^2 =1-(2+3+2√6) =-4-2√6 (1)5√12×√18 =5*2√3*3√2 =30√6; (2)-6√45×(-4√48) =6*3√5*4*4√3 =288√15; (3)√(12a)×√(3a) /4 =√(36a^2)/4 =6a/4 =3a/2. 5. x^2(y+z)^2-2xy(x-z)(y+z)+y^2(x-z)^2 =[x(y+z)-y(x-z)]^2 =(xz+yz)^2 =z^2(x+y)^2 6. 3(a+2)^2+28(a+2)-20 =[3(a+2)-2][(a+2)+10] =(3a+4)(a+12) 7. (a+b)^2-(b-c)^2+a^2-c^2 =(a+b)^2-c^2+a^2-(b-c)^2 =(a+b+c)(a+b-c)+(a+b-c)(a-b+c) =(a+b-c)(a+b+c+a-b+c) =2(a+b-c)(a+c) 8. x(x+1)(x^2+x-1)-2 =(x^2+x)(x^2+x-1)-2 =(x^2+x)^2-(x^2+x)-2 =(x^2+x-2)(x^2+x+1) =(x+2)(x-1)(x^2+x+1) 9. 9x^2(x-1)^2-3(x^2-x)-56 =9x^2(x-1)^2-3x(x-1)-56 =[3x(x-1)-8][3x(x-1)+7] =(3x^2-3x-8)(3x^2-3x+7) 有理数练习 练习一(B级) (一)计算题: (1)23+(-73) (2)(-84)+(-49) (3)7+(-2.04) (4)4.23+(-7.57) (5)(-7/3)+(-7/6) (6)9/4+(-3/2) (7)3.75+(2.25)+5/4 (8)-3.75+(+5/4)+(-1.5) 5. x^2(y+z)^2-2xy(x-z)(y+z)+y^2(x-z)^2 =[x(y+z)-y(x-z)]^2 =(xz+yz)^2 =z^2(x+y)^2 6. 3(a+2)^2+28(a+2)-20 =[3(a+2)-2][(a+2)+10] =(3a+4)(a+12) 7. (a+b)^2-(b-c)^2+a^2-c^2 =(a+b)^2-c^2+a^2-(b-c)^2 =(a+b+c)(a+b-c)+(a+b-c)(a-b+c) =(a+b-c)(a+b+c+a-b+c) =2(a+b-c)(a+c) 8. x(x+1)(x^2+x-1)-2 =(x^2+x)(x^2+x-1)-2 =(x^2+x)^2-(x^2+x)-2 =(x^2+x-2)(x^2+x+1) =(x+2)(x-1)(x^2+x+1) 9. 9x^2(x-1)^2-3(x^2-x)-56 =9x^2(x-1)^2-3x(x-1)-56 =[3x(x-1)-8][3x(x-1)+7] =(3x^2-3x-8)(3x^2-3x+7) 1.125*3+125*5+25*3+25 2.9999*3+101*11*(101-92) 3.(23/4-3/4)*(3*6+2) 4. 3/7 × 49/9 - 4/3 5. 8/9 × 15/36 + 1/27 6. 12× 5/6 – 2/9 ×3 7. 8× 5/4 + 1/4 8. 6÷ 3/8 – 3/8 ÷6 9. 4/7 × 5/9 + 3/7 × 5/9 10. 5/2 -( 3/2 + 4/5 ) 11. 7/8 + ( 1/8 + 1/9 ) 12. 9 × 5/6 + 5/6 13. 3/4 × 8/9 - 1/3 14. 7 × 5/49 + 3/14 15. 6 ×( 1/2 + 2/3 ) 16. 8 × 4/5 + 8 × 11/5 17. 31 × 5/6 – 5/6 18. 9/7 - ( 2/7 – 10/21 ) 19. 5/9 × 18 – 14 × 2/7 20. 4/5 × 25/16 + 2/3 × 3/4 21. 14 × 8/7 – 5/6 × 12/15 22. 17/32 – 3/4 × 9/24 23. 3 × 2/9 + 1/3 24. 5/7 × 3/25 + 3/7 25. 3/14 ×× 2/3 + 1/6 26. 1/5 × 2/3 + 5/6 27. 9/22 + 1/11 ÷ 1/2 28. 5/3 × 11/5 + 4/3 29. 45 × 2/3 + 1/3 × 15 30. 7/19 + 12/19 × 5/6 31. 1/4 + 3/4 ÷ 2/3 32. 8/7 × 21/16 + 1/2 33. 101 × 1/5 – 1/5 × 21 34.50+160÷40 35.120-144÷18+35 36.347+45×2-4160÷52 37(58+37)÷(64-9×5) 38.95÷(64-45) 39.178-145÷5×6+42 40.812-700÷(9+31×11) 41.85+14×(14+208÷26) 43.120-36×4÷18+35 44.(58+37)÷(64-9×5) 45.(6.8-6.8×0.55)÷8.5 46.0.12× 4.8÷0.12×4.8 47.(3.2×1.5+2.5)÷1.6 48.6-1.6÷4= 5.38+7.85-5.37= 49.7.2÷0.8-1.2×5= 6-1.19×3-0.43= 50.6.5×(4.8-1.2×4)= 51.5.8×(3.87-0.13)+4.2×3.74 52.32.52-(6+9.728÷3.2)×2.5 53.[(7.1-5.6)×0.9-1.15] ÷2.5 54.5.4÷[2.6×(3.7-2.9)+0.62] 55.12×6÷(12-7.2)-6 56.12×6÷7.2-6 57.0.68×1.9+0.32×1.9 58.58+370)÷(64-45) 59.420+580-64×21÷28 60.136+6×(65-345÷23) 15-10.75×0.4-5.7 62.18.1+(3-0.299÷0.23)×1 63.(6.8-6.8×0.55)÷8.5 64.0.12× 4.8÷0.12×4.8 65.(3.2×1.5+2.5)÷1.6 66.3.2×6+(1.5+2.5)÷1.6 67.0.68×1.9+0.32×1.9 68.10.15-10.75×0.4-5.7 69.5.8×(3.87-0.13)+4.2×3.74 70.32.52-(6+9.728÷3.2)×2.5 71.[(7.1-5.6)×0.9-1.15] ÷2.5 72.5.4÷[2.6×(3.7-2.9)+0.62] 73.12×6÷(12-7.2)-6 74.12×6÷7.2-6 75.33.02-(148.4-90.85)÷2.5 1) 76.(25%-695%-12%)*36 77./4*3/5+3/4*2/5 78.1-1/4+8/9/7/9 79.+1/6/3/24+2/21 80./15*3/5 81.3/4/9/10-1/6 82./3+1/2)/5/6-1/3]/1/7 83./5+3/5/2+3/4 84.(2-2/3/1/2)]*2/5 85.+5268.32-2569 86.3+456-52*8 87.5%+6325 88./2+1/3+1/4 2) 89+456-78 3) 5%+. 3/7 × 49/9 - 4/3 4) 9 × 15/36 + 1/27 5) 2× 5/6 – 2/9 ×3 6) 3× 5/4 + 1/4 7) 94÷ 3/8 – 3/8 ÷6 8) 95/7 × 5/9 + 3/7 × 5/9 9) 6/2 -( 3/2 + 4/5 ) 10) 8 + ( 1/8 + 1/9 ) 11) 8 × 5/6 + 5/6 12) 1/4 × 8/9 - 1/3 13) 10 × 5/49 + 3/14 14) 1.5 ×( 1/2 + 2/3 ) 15) 2/9 × 4/5 + 8 × 11/5 16) 3.1 × 5/6 – 5/6 17) 4/7 - ( 2/7 – 10/21 ) 18) 19 × 18 – 14 × 2/7 19) 5 × 25/16 + 2/3 × 3/4 20) 4 × 8/7 – 5/6 × 12/15 21) 7/32 – 3/4 × 9/24 22) 1、 2/3÷1/2-1/4×2/5 2、 2-6/13÷9/26-2/3 3、 2/9+1/2÷4/5+3/8 4、 10÷5/9+1/6×4 5、 1/2×2/5+9/10÷9/20 6、 5/9×3/10+2/7÷2/5 7、 1/2+1/4×4/5-1/8 8、 3/4×5/7×4/3-1/2 9、 23-8/9×1/27÷1/27 10、 8×5/6+2/5÷4 11、 1/2+3/4×5/12×4/5 12、 8/9×3/4-3/8÷3/4 13、 5/8÷5/4+3/23÷9/11 23) 1.2×2.5+0.8×2.5 24) 8.9×1.25-0.9×1.25 25) 12.5×7.4×0.8 26) 9.9×6.4-(2.5+0.24)(27) 6.5×9.5+6.5×0.5 0.35×1.6+0.35×3.4 0.25×8.6×4 6.72-3.28-1.72 0.45+6.37+4.55 5.4+6.9×3-(25-2.5)2×41846-620-380 4.8×46+4.8×54 0.8+0.8×2.5 1.25×3.6×8×2.5-12.5×2.4 28×12.5-12.5×20 23.65-(3.07+3.65) (4+0.4×0.25)8×7×1.25 1.65×99+1.65 27.85-(7.85+3.4) 48×1.25+50×1.25×0.2×8 7.8×9.9+0.78 (1010+309+4+681+6)×12 3×9146×782×6×854 5.15×7/8+6.1-0.60625 1. 3/7 × 49/9 - 4/3 2. 8/9 × 15/36 + 1/27 3. 12× 5/6 – 2/9 ×3 4. 8× 5/4 + 1/4 5. 6÷ 3/8 – 3/8 ÷6 6. 4/7 × 5/9 + 3/7 × 5/9 7. 5/2 -( 3/2 + 4/5 ) 8. 7/8 + ( 1/8 + 1/9 ) 9. 9 × 5/6 + 5/6 10. 3/4 × 8/9 - 1/3 11. 7 × 5/49 + 3/14 12. 6 ×( 1/2 + 2/3 ) 13. 8 × 4/5 + 8 × 11/5 14. 31 × 5/6 – 5/6 15. 9/7 - ( 2/7 – 10/21 ) 16. 5/9 × 18 – 14 × 2/7 17. 4/5 × 25/16 + 2/3 × 3/4 18. 14 × 8/7 – 5/6 × 12/15 19. 17/32 – 3/4 × 9/24 20. 3 × 2/9 + 1/3 21. 5/7 × 3/25 + 3/7 22. 3/14 ×× 2/3 + 1/6 23. 1/5 × 2/3 + 5/6 24. 9/22 + 1/11 ÷ 1/2 25. 5/3 × 11/5 + 4/3 26. 45 × 2/3 + 1/3 × 15 27. 7/19 + 12/19 × 5/6 28. 1/4 + 3/4 ÷ 2/3 29. 8/7 × 21/16 + 1/2 30. 101 × 1/5 – 1/5 × 21 31.50+160÷40 (58+370)÷(64-45) 32.120-144÷18+35 33.347+45×2-4160÷52 34(58+37)÷(64-9×5) 35.95÷(64-45) 36.178-145÷5×6+42 420+580-64×21÷28 37.812-700÷(9+31×11) (136+64)×(65-345÷23) 38.85+14×(14+208÷26) 39.(284+16)×(512-8208÷18) 40.120-36×4÷18+35 41.(58+37)÷(64-9×5) 42.(6.8-6.8×0.55)÷8.5 43.0.12× 4.8÷0.12×4.8 44.(3.2×1.5+2.5)÷1.6 (2)3.2×(1.5+2.5)÷1.6 45.6-1.6÷4= 5.38+7.85-5.37= 46.7.2÷0.8-1.2×5= 6-1.19×3-0.43= 47.6.5×(4.8-1.2×4)= 0.68×1.9+0.32×1.9 48.10.15-10.75×0.4-5.7 49.5.8×(3.87-0.13)+4.2×3.74 50.32.52-(6+9.728÷3.2)×2.5 51.[(7.1-5.6)×0.9-1.15] ÷2.5 52.5.4÷[2.6×(3.7-2.9)+0.62] 53.12×6÷(12-7.2)-6 (4)12×6÷7.2-6 102×4.5 7.8×6.9+2.2×6.9 5.6×0.25 8×(20-1.25) 1)127+352+73+44 (2)89+276+135+33 (1)25+71+75+29 +88 (2)243+89+111+57 9405-2940÷28×21 920-1680÷40÷7 690+47×52-398 148+3328÷64-75 360×24÷32+730 2100-94+48×54 51+(2304-2042)×23 4215+(4361-716)÷81 (247+18)×27÷25 36-720÷(360÷18) 1080÷(63-54)×80 (528+912)×5-6178 8528÷41×38-904 264+318-8280÷69 (174+209)×26- 9000 814-(278+322)÷15 1406+735×9÷45 3168-7828÷38+504 796-5040÷(630÷7) 285+(3000-372)÷36 1+5/6-19/12 3x(-9)+7x(-9 (-54)x1/6x(-1/3) 1.18.1+(3-0.299÷0.23)×1 2.(6.8-6.8×0.55)÷8.5 3.0.12× 4.8÷0.12×4.8 4.(3.2×1.5+2.5)÷1.6 (2)3.2×(1.5+2.5)÷1.6 5.6-1.6÷4= 5.38+7.85-5.37= 6.7.2÷0.8-1.2×5= 6-1.19×3-0.43= 7.6.5×(4.8-1.2×4)= 0.68×1.9+0.32×1.9 8.10.15-10.75×0.4-5.7 9.5.8×(3.87-0.13)+4.2×3.74 10.32.52-(6+9.728÷3.2)×2.5 11.[(7.1-5.6)×0.9-1.15] ÷2.5 12.5.4÷[2.6×(3.7-2.9)+0.62] 13.12×6÷(12-7.2)-6 14.12×6÷7.2-6 15.33.02-(148.4-90.85)÷2.5 7×(5/21+9/714) a^3-2b^3+ab(2a-b) =a^3+2a^2b-2b^3-ab^2 =a^2(a+2b)-b^2(2b+a) =(a+2b)(a^2-b^2) =(a+2b)(a+b)(a-b) 2. (x^2+y^2)^2-4y(x^2+y^2)+4y^2 =(x^2+y^2-2y)^2 3. (x^2+2x)^2+3(x^2+2x)+x^2+2x+3 =(x^2+2x)^2+4(x^2+2x)+3 =(x^2+2x+3)(x^2+2x+1) =(x^2+2x+3)(x+1)^2 4. (a+1)(a+2)+(2a+1)(a-2)-12 =a^2+3a+2+2a^2-3a-2-12 =3a^2-12 =3(a+2)(a-2) 5. x^2(y+z)^2-2xy(x-z)(y+z)+y^2(x-z)^2 =[x(y+z)-y(x-z)]^2 =(xz+yz)^2 =z^2(x+y)^2 6. 3(a+2)^2+28(a+2)-20 =[3(a+2)-2][(a+2)+10] =(3a+4)(a+12) 7. (a+b)^2-(b-c)^2+a^2-c^2 =(a+b)^2-c^2+a^2-(b-c)^2 =(a+b+c)(a+b-c)+(a+b-c)(a-b+c) =(a+b-c)(a+b+c+a-b+c) =2(a+b-c)(a+c) 8. x(x+1)(x^2+x-1)-2 =(x^2+x)(x^2+x-1)-2 =(x^2+x)^2-(x^2+x)-2 =(x^2+x-2)(x^2+x+1) =(x+2)(x-1)(x^2+x+1) 写完一遍后再别这些题写一遍,以此类推,老师们看作业都是一看而过不会一个一个批的。

以上就是数学初二计算题及答案的全部内容,解解:(1)由勾股定理,得斜边= = ;(2)设正方形边长为a,则a2=S,解得a= ;(3)由h=5t2,得t2= ,开平方得t= (舍去负值).故本题答案为: , , .100道没有那么多。

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