Question

先去括号，再合并同类项：2(2n-3m)-(2m-3n)还有(x-2y+1)-3(2x-y-2)

那个x不是乘号.........还有一题.....已知a-b=3,c+d=2,求(b+c)-(a-d)的值 一定要快 要对呀...........嘻嘻
回答问题的时候分第1第2.3题 我好看清楚........................呵呵 里面有三题

Answer 1

2(2n-3m)-(2m-3n)
=4n-6m-2m+3n
=7n-8m

(x-2y+1)-3(2x-y-2)
=x-2y+1-6x+3y+6
=-5x+y+7

已知a-b=3,c+d=2,
(b+c)-(a-d)
=b+c-a+d
=-(a-b)+c+d
=-3+2
=-1

Answer 2

解：1） 2(2n-3m)-(2m-3n) 3. 解： 因为 a-b=3,c+d=2,
=4n-6m-2m+3n 所以 b-a=-3 ，c+d =2
=4n+3n+(-6m-2m) 则（b+c)-(a-d)=b+c-a+d
=7n-8m =(b-a)+(c+d)
=-3+2
=-1
2） (x-2y+1)-3(2x-y-2)
=x-6x+3y-2y+1+6
=-5x+y+7

Answer 3

2(2n-3m)-(2m-3n)=4n-6m-2m+3n=7n-8m
(x-2y+1)-3(2x-y-2)=x-2y+1-6x+3y+6=-5x+y+7

(b+c)-(a-d)=-a+b+c+d=-(a-b)+(c+d)=-3+2=-1

Answer 4

（1）2(2n-3m)-(2m-3n)
=4n-6m-2m+3n
=7n-8m
（2）(x-2y+1)-3(2x-y-2)
=x-2y+1-6x+3y+6
=-5x+y+7
（3）已知a-b=3,c+d=2,
(b+c)-(a-d)
=b+c-a+d
=-(a-b)+c+d
=-3+2
=-1