先化简,再求值:(2x2-3y3)(-2x2-3y3)-(-2x2-3y3)2,其中x、y满足|x+1|与(1-y)2互为相反数.
问题描述:
先化简,再求值:(2x2-3y3)(-2x2-3y3)-(-2x2-3y3)2,其中x、y满足|x+1|与(1-y)2互为相反数.
答
∵|x+1|与(1-y)2互为相反数,即|x+1|+(1-y)2=0,∴x+1=0,1-y=0,解得x=-1,y=1,∴(2x2-3y3)(-2x2-3y3)-(-2x2-3y3)2,=9y6-4x4-(4x4+12x2y3+9y3),=9y6-4x4-4x4-12x2y3-9y3,=-8x4-12x2y3,=-8-12×1×...