化简求值(x²-4y²)/(4x²-8xy)其中x=2,y=-3
问题描述：
化简求值(x²-4y²)/(4x²-8xy)其中x=2,y=-3
答
解
(x²-4y²)/(4x²-8xy)
=(x-2y)(x+2y)/4x(x-2y)
=(x+2y)/4x
=(2-3×2)/(4×2)
=-4/8
=-1/2