先化简,再求值:[4(xy-1)^2-(xy+2)(2-xy)]÷(1/4xy),其中x=-2 y=1/4_数学解答

先化简,再求值:[4(xy-1)^2-(xy+2)(2-xy)]÷(1/4xy),其中x=-2 y=1/4

人气：398 ℃　时间：2020-04-04 11:48:27

解答

原式=(4x²y²-8xy+4-4+x²y²)÷(1/4xy)
=(5x²y²-8xy)÷(1/4xy)
=20xy-32
=20*(-2)*(1/4)-32
=-10-32
=-42