5x^2+6xy-8y^2
=5x^2+10xy-4xy-8y^2
=5x(x+2y)-4y(x+2y)
=(x+2y)(5x-4y)
如还不明白,请继续追问.
手机提问的朋友在客户端右上角评价点【满意】即可.