先化简,再求值：｛(x+2y)(x-2y）+4(x-y)²｝÷6x,其中x=12,y=3.

题目

先化简,再求值：｛(x+2y)(x-2y）+4(x-y)²｝÷6x,其中x=12,y=3.

答案

｛(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