分解因式16(x+y)²+40(x-y)²+25(x-y)²
问题描述：
分解因式16(x+y)²+40(x-y)²+25(x-y)²
答
错了,中间是+40(x²-y²)
原式=[4(x+y)]²+2[4(x+y)][5(x-y)]+[5(x-y)]²
=[4(x+y)+5(x-y)]²
=(9x-y)²