已知4x-3y=2,求代数式[(x^2 +2y)^2+4y(x-y)]/(-2y)的值
问题描述：
已知4x-3y=2,求代数式[(x^2 +2y)^2+4y(x-y)]/(-2y)的值
答
[(x+2y^2)^2-(x+y^2)(x-y^2)-5y^4]/2y
=[x^2+4xy^2+4y^4-(x^2-y^4)-5y^4]/2y
=[x^2+4xy^2+4y^4-x^2+y^4-5y^4]/2y
=[x^2-x^2+4xy^2+4y^4+y^4-5y^4]/2y
=4xy^2/2y
=2xy
∴原式=4