(5x-y)(y+5x)-(3y+2x)(3y-2x) x=1 y=2先化简再求值
问题描述:
(5x-y)(y+5x)-(3y+2x)(3y-2x) x=1 y=2
先化简再求值
答
(5x-y)(y+5x)-(3y+2x)(3y-2x)
=25x²-y²-9y²+4x²
=29x²-10y²
=29-40
=-11