已知x+3y=12,则(x平方+2xy - 3y平方)除以(x-y)等于多少
问题描述:
已知x+3y=12,则(x平方+2xy - 3y平方)除以(x-y)等于多少
答
(x平方+2xy - 3y平方)除以(x-y)
=(x-y)(x+3y)/(x-y)
=x+3y
=12