初一數學化簡題,再求值20題,初一數學題,先化簡再求值的題帶答案

2022-05-23 08:26:31 字數 5308 閱讀 4316

1樓:充珈藍石

1、x-(x-1)/2=2-(x-2)/3 x-x/2+1/2=2-x/3+2/3 x/2+x/3=2+2/3-1/2 5x/6=13/6 x=13/5 2、(x-1)/2-(2x-7)/6=(4x-5)/3-1 x/2-1/2-x/3+7/6=4x/3-5/3-1 7/6-1/2+1+5/3=4x/3+x/3-x/2 10/3=7x/6 x=30/7 3、3(2x-1)=2(1-x)-1 6x-3=2-2x-1 8x=2-1+3 8x=4 x...

2樓:

3ab-4ab+8ab-7ab+ab 23a3bc2-15ab2c+8abc-24a3bc2-8abc 2y+(-2y+5)-(3y+2) (2x2-3xy+4y2)+(x2+2xy-3y2) 2a-(3a-2b+2)+(3a-4b-1) 2x-(x+3y)-(-x-y)-(x-y) 2x+2y-[3x-2(x-y)] 5-(1-x)-1-(x-1) 3x-2x2+x-4+2x3-5x+3 3x-2x+x-4-(2x3-5x+3) -(2x2-y2)...

七年級,簡單些的先化簡再求值數學計算題,並帶答案,二十道,急急急急急!!!求幫忙qaq

3樓:小鈴鐺

9x 6x^2 -3(x-2/3x^2).其中x=-2 9x 6x -3(x-2/3x) =9x 6x-3x 2x =8x 6x =8×(-2) 6×(-2) =32-12 =20 1/4(-4x^2 2x-8)-(1/2x-1),其中x=1/2 1/4(-4x 2x-8)-(1/2x-1) =-x 1/2x-2-1/2x 1 =-x-1 =-(1/2)-1 =-1/4-1 =-5/4 (1) 5a-2b 3b-4a-1 a= -1 b=2 (2)7x-3x-2x-2x=5=6x x= -2 (3)2x―[6-2(x-2)] 其中 x=-2 (4).(5a+2a-3-4a)-(-a+3a-a),其中a=-2 (5)3x 4x-2x-x x-3x-1 其中x= -3 (6)-3[y-(3x2-3xy)]-[y 2(4x2-4xy)],其中x=2, y=1/2 (7)2x-3xy y-2xy-2x 5xy-2y 1 其中x=22/7 (8)2xy 4xy-3xy-5xy 其中x=1 y= -1 (9)9x 6x2 -3(x-2/3x2).其中x=-2 (10)1/4(-4x 2x-8)-(1/2x-1) 其中x=1/2 (11)3x'y-[2x'y-(2xyz-x'z)-4x'z]-xyz,其中x=-2,y=-3,z=1, 、(12)(5a^2-3b^2) (a^2 b^2)-(5a^2 3b^2),其中a=-1,b=1 (13)2(a^2b ab^2)-2(a^2 b-1)-2ab^2 -2其中a=-2,b=2 (14)(3x-5y) (-3 y)其中x=5,y=3 (15).

【(x 1)(x 2)-2】÷x,其中x=-3

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

(7) 47x-40y=853

34x-y=2006

答案:x=59 y=48

(8) 19x-32y=-1786

75x+y=4950

4樓:從潔雅

……先把原式子化簡,再帶入即可

初一數學題,先化簡再求值的題帶答案

5樓:匿名使用者

3ab-4ab+8ab-7ab+ab=______.5a+3b-2a+(2b+3b)=______2a-b2+c-d3=2a+( )-d3=2a-d3-( )=c-( ).

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

=x+5y

已知x<0,y<0,化簡|x+y|-|5-x-y|=______..-7x2+6x+13x2-4x-5x2=______.3b+5a-5b+10b=______

化簡代數式x-[y-2x-(x+y)]等於______.

6樓:8冰藍水蜜桃

①2a-(3a-2b+2)+(3a-4b-1) =( )=2a-3a+2b-2+3a-4b-1

=(2-3+3)a+(2-4)b+(-2-1)=2a-2b-3

②5-(1-x)-1-(x-1)=( )=5-1+x-1-x+1

=4③2x-(x+3y)-(-x-y)-(x-y)=( )=2x-x+3y+x+y-x+y

=x+5y純手工

7樓:一生一世攜白頭

3ab-4ab+8ab-7ab+ab=ab a=1b=2 ab=1x2= 2

2x-(x+3y)-(-x-y)-(x-y)=2x-x-3y+x+y-x+y=x-y x=6 y=2 x-y=6-2=4

8樓:清風習來

3.3ab-4ab+8ab-7ab+ab=______.

4.7x-(5x-5y)-y=______.

5.23a3bc2-15ab2c+8abc-24a3bc2-8abc=______.

6.-7x2+6x+13x2-4x-5x2=______.

7.2y+(-2y+5)-(3y+2)=______.

11.(2x2-3xy+4y2)+(x2+2xy-3y2)=______.

12.2a-(3a-2b+2)+(3a-4b-1)=______.

13.-6x2-7x2+15x2-2x2=______.

14.2x-(x+3y)-(-x-y)-(x-y)=______.

16.2x+2y-[3x-2(x-y)]=______.

17.5-(1-x)-1-(x-1)=______.

18.( )+(4xy+7x2-y2)=10x2-xy.

19.(4xy2-2x2y)-( )=x3-2x2y+4xy2+y3.

21.已知a=x3-2x2+x-4,b=2x3-5x+3,計算a+b=______.

22.已知a=x3-2x2+x-4,b=2x3-5x+3,計算a-b=______.

23.若a=-0.2,b=0.5,代數式-(|a2b|-|ab2|)的值為______.

25.乙個多項式減去3m4-m3-2m+5得-2m4-3m3-2m2-1,那麼這個多項式等於______.

26.-(2x2-y2)-[2y2-(x2+2xy)]=______.

27.若-3a3b2與5ax-1by+2是同類項,則x=______,y=______.

28.(-y+6+3y4-y3)-(2y2-3y3+y4-7)=______.

29.化簡代數式4x2-[7x2-5x-3(1-2x+x2)]的結果是______.

30.2a-b2+c-d3=2a+( )-d3=2a-d3-( )=c-( ).

31.3a-(2a-3b)+3(a-2b)-b=______.

32.化簡代數式x-[y-2x-(x+y)]等於______.

33.[5a2+( )a-7]+[( )a2-4a+( )]=a2+2a+1.

34.3x-[y-(2x+y)]=______.

35.化簡|1-x+y|-|x-y|(其中x<0,y>0)等於______.

36.已知x≤y,x+y-|x-y|=______.

37.已知x<0,y<0,化簡|x+y|-|5-x-y|=______.

38.4a2n-an-(3an-2a2n)=______.

39.若乙個多項式加上-3x2y+2x2-3xy-4得

2x2y+3xy2-x2+2xy,

則這個多項式為______.

40.-5xm-xm-(-7xm)+(-3xm)=______.

41.當a=-1,b=-2時,

[a-(b-c)]-[-b-(-c-a)]=______.

43.當a=-1,b=1,c=-1時,

-[b-2(-5a)]-(-3b+5c)=______.

44.-2(3x+z)-(-6x)+(-5y+3z)=______.

45.-5an-an+1-(-7an+1)+(-3an)=______.

46.3a-(2a-4b-6c)+3(-2c+2b)=______.

48.9a2+[7a2-2a-(-a2+3a)]=______.

50.當2y-x=5時,5(x-2y)2-3(-x+2y)-100=_____

數學七年級先化簡再求值題目,越多越好…(有答案)

9樓:匿名使用者

1.先化簡,再求bai值:du

[(a+b)(a-b) -(a-b)2+2b(a-b)]÷zhi4b,a=2,b=-2.

2.已知x+y=7,xy=2,求①2x2+2y2的值dao;②回(x-y)2的值.

1、a-b,4

2、(答1)90

(2)41

初一上期末數學先化簡再求值的題

10樓:凌月霜丶

3.3ab-4ab+8ab-7ab+ab=______.

4.7x-(5x-5y)-y=______.

5.23a3bc2-15ab2c+8abc-24a3bc2-8abc=______.

6.-7x2+6x+13x2-4x-5x2=______.

7.2y+(-2y+5)-(3y+2)=______.

11.(2x2-3xy+4y2)+(x2+2xy-3y2)=______.

12.2a-(3a-2b+2)+(3a-4b-1)=______.

13.-6x2-7x2+15x2-2x2=______.

14.2x-(x+3y)-(-x-y)-(x-y)=______.

16.2x+2y-[3x-2(x-y)]=______.

17.5-(1-x)-1-(x-1)=______.

18.( )+(4xy+7x2-y2)=10x2-xy.

19.(4xy2-2x2y)-( )=x3-2x2y+4xy2+y3.

21.已知a=x3-2x2+x-4,b=2x3-5x+3,計算a+b=______.

22.已知a=x3-2x2+x-4,b=2x3-5x+3,計算a-b=______.

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