( 解方程,｛(x+2)²-(y+4)²=(x+y)(x-y),x-3y=-2,运用平方差
问题描述：
( 解方程,｛(x+2)²-(y+4)²=(x+y)(x-y),x-3y=-2,运用平方差
答
(x+2)²-(y+4)²=(x+y)(x-y),
(x+2+y+4)(x+2-y-4)=x^2-y^2
x = 3 + 2 y
x-3y=-2
3+2y-3y=-2
3+2=y
y=5
x=3+2*5=13