已知x²-12xy-28y²=0(x≠0,y≠0),求(2x+3y)/28
问题描述:
已知x²-12xy-28y²=0(x≠0,y≠0),求(2x+3y)/28
答
x²-12xy-28y²=0
(x-14y)(x+2y)=0
x=14y或x=-2y
(2x+3y)/28=(28y+3y)/28=31y/28
(2x+3y)/28=(-4y+3y)/28=-y/28