1、(1)原式=(a+b)[3(x+y)-(x-y)]
=(a+b)(2x+4y)
=2(a+b)(x+2y)
(2)原式=x(x-y)²(a-b)-(x-y)²(a-b)
=(x-y)²(a-b)(x-1)
2、坦卜正由已知的x=-2,y=1/2
原式=(x+y)(y+x-y)
=x(x+y)
=-2(-2+1/2)
=3
3、x²弊陆(a-b)+y²(b-a)
=x²(a-b)-y²(让悔a-b)
=(a-b)(x²-y²)
=(a-b)(x-y)(x+y)
我想帮你,可是手机太不方便了!