分解公因式2题

问题描述:

分解公因式2题
(x-2y+3y)²
(-x+y)(-y-x)
(-2x²+1/2)(-2x²-1/2)

(x-2y+3y)²=(x+y)²=x²+2xy+y²
(-x+y)(-y-x)=xy+x²-y²-xy=x²-y²