问题
解答题
先化简,再求值:3x2y-[5xy2+2(x2y-
|
答案
原式=3x2y-[5xy2+2x2y-1+x2y]+6xy2
=3x2y-5xy2-3x2y+1+6xy2
=xy2+1,
当x=-2,y=
时,原式=-2×(1 2
)2+1=1 2
.1 2
先化简,再求值:3x2y-[5xy2+2(x2y-
|
原式=3x2y-[5xy2+2x2y-1+x2y]+6xy2
=3x2y-5xy2-3x2y+1+6xy2
=xy2+1,
当x=-2,y=
时,原式=-2×(1 2
)2+1=1 2
.1 2