Question

因式分解和计算 初二

(a-b)(x-y)-(b-a)(x+y)=? 因式分解
3(y-2)²-（2y+2）(-2+2y) [x(x²y²-xy)-y(x²-x{的三次方}y)]÷3x²y 计算
第三个那里是x的三次方

Answer 1

(1).将后面的（b-a）变成-（a-b）
可以得到：(a-b)(x-y)+(a-b)(x+y)=(a-b)[(x-y)+(x+y)]=(a-b)(2x)=2x(a-b)
(2).原式=3(y²+4-4y)-4(y+1)(y-1)=3y²+12-12y-4(y²-1)=-y²-12y+16
(3).[x(x²y²-xy)-y(x²-x{的三次方}y)]÷3x²y =[x²y(xy-1)-x²y(1-xy)]÷3x²y =[x²y(xy-1-1+xy)]÷3x²y=[x²y(2xy-2)]/3x²y=2/3（xy-1）

其中涉及到的公式：ab+cb=(a+c)b (a+b)²=a²+b²+2ab (a+b)(a-b)=a²-b²

Answer 2

1、=（a-b)(x-y)+(a-b)(x+y) 2、=3y²-6y+12-（2y²-2²)=3y²-6y+12-4y²+4=-y²-6y+16
=(a-b)(x-y+x+y) =-(y²+6y-16)=-(y-2)(y+8)
=(a-b)2x
3、=（x³y²-x²y-x²y-x³y²）÷3x²y=－2x²y÷3x²y＝－2／3

Answer 3

(a-b)(x-y)-(b-a)(x+y)=(a-b)(x-y)+(a-b)(x+y)=(a-b)*(x-y+x+y)=2x(a-b)找到相同的因a-b就OK啦

3(y-2)2-（2y+2）(-2+2y) =3(y-2)2-（2y+2）(2y-2) =3(y-2)2-（4y2-4)=化简得-y2-12y+16你们现在学的还能再因式分解么，要不就是您题目抄错

[x(x2y2-xy)-y(x2-x{的三次方}y)]÷3x2y = [x*xy(xy-1)-y*x2(1-xy)]÷3x2y = [x2y(xy-1)-x2y(1-xy)]÷3x2y
=x2y[(xy-1)-(1-xy)]÷3x2y=[(xy-1)-(1-xy)]÷3自己化简把