先化简再求值[﹙y-3x﹚﹙-3x-y﹚-9﹙x-2y﹚²]÷3y,其中x=-2,y=3
问题描述:
先化简再求值[﹙y-3x﹚﹙-3x-y﹚-9﹙x-2y﹚²]÷3y,其中x=-2,y=3
答
[﹙y-3x﹚﹙-3x-y﹚-9﹙x-2y﹚²]÷3y
=[9x²-y²-9﹙x²-4xy+4y²)]÷3y
=(9x²-y²-9x²+36xy-36y²)÷3y
=(36xy-37y²)÷3y
=(36x-37y)÷3
=12x-37y/3
=12*(-2)-37*3/3
=-24-37
=-61