(x+3y+2)(x-3y+2)
问题描述:
(x+3y+2)(x-3y+2)
答
=(x+2)^2-9y^2
=x^2+4+4x-9y^2
(x+3y+2)(x-3y+2)
=(x+2)^2-9y^2
=x^2+4+4x-9y^2