Question

数学快快快快

（×+y）²-16（×-y）²

Answer 1

(x+y)²-16(x-y)²
=[(x+y)+4(x-y)][(x+y)-4(x-y)]
=(5x-3y)(5y-x)

追问

不对=(5x-3y)(5y-3x) 你看你那里错了

追答

(x+y)²-16(x-y)²
=[(x+y)+4(x-y)][(x+y)-4(x-y)]
=(5x-3y)(5y-3x)
打错了.想的是3x,打的时候忘了3了.