先化简,再求值:{(x+2y)(x-2y)+4(x-y)²}÷6x,其中x=12,y=3.
问题描述:
先化简,再求值:{(x+2y)(x-2y)+4(x-y)²}÷6x,其中x=12,y=3.
答
{(x+2y)(x-2y)+4(x-y)2}÷6x
=(x²-4y²+4x²-8xy+4y²)÷6x
=(5x²-8xy)÷6x
=(5x-8y)÷6
=(5×12-8×3)÷6
=(60-24)÷6
=36÷6
=6
祝你开心