先化简,再求值.x²y²-4)（-x²y²-4)-4(xy-1/2)·(xy-1\2),其中x=1,y=-2.

先化简,再求值.x²y²-4)（-x²y²-4)-4(xy-1/2)·(xy-1\2),其中x=1,y=-2.
先化简,再求值.x²y²-4)（-x²y²-4)-4(xy-1/2)·(xy-1\2),其中x=1,y=-2.

先化简,再求值.x²y²-4)（-x²y²-4)-4(xy-1/2)·(xy-1\2),其中x=1,y=-2.
(x²y²-4)（-x²y²-4)-4(xy-1/2)·(xy-1\2),
=-[(xy)²-4²]-4(xy-1/2)²
=-[(-2)²-4²]-4(-2-1/2)²
=-(4-16)-4*(5/2)²
=12-4*25/4
=12-25
=-13