化简,在求值:(x-y)(x-2y)+(x+2y)(x-3y),其中x=4,y=1.5.
问题描述:
化简,在求值:(x-y)(x-2y)+(x+2y)(x-3y),其中x=4,y=1.5.
答
(x-y)(x-2y)+(x+2y)(x-3y)
=2x²-4xy-4y²
=-1