7(x-1)2+4(x-1)(y+2)-20(y+2)2 8x2y2+6xy-35 2(a+b)2+(a+b)(a-b)-6(a-b)2
问题描述：
7(x-1)2+4(x-1)(y+2)-20(y+2)2 8x2y2+6xy-35 2(a+b)2+(a+b)(a-b)-6(a-b)2
7（x-1）²+4（x-1）（y+2）-20（y+2）²
8x²y²+6xy-35
2(a+b)²+(a+b)(a-b)-6(a-b)²
答
7(x-1)^2+4(x-1)(y+2)-20(y+2)^2
=[7(x-1)-10(y+2)][(x-1)+2(y+2)]
=(7x-7-10y-20)(x-1+2y+4)
=(7x-10y-27)(x+2y+3)
其他的我不会了~抱歉~