化简求值：2xy-1/2(4xy-8x^2y^2)+2(3xy-5x^2y^2),其中x=1/2,y=-2/3_数学解答

化简求值：2xy-1/2(4xy-8x^2y^2)+2(3xy-5x^2y^2),其中x=1/2,y=-2/3

人气：453 ℃　时间：2019-10-19 17:07:39

解答

原式=2xy-2xy+4x^2y^2+6xy-10x^2y^2
=6xy-6x^2y^2
=6xy(1-xy)
xy= - 1/3 ∴原式= - 2X4/3= - 8/3