先化简,再求值:3x2y?[5xy2+2(x2y?12)+x2y ]+6xy2,其中x=?2,y=12

先化简,再求值:3x2y?[5xy2+2(x2y?12)+x2y ]+6xy2,其中x=?2,y=12.
2025-05-20 15:24:48
推荐回答(1个)
回答1:

原式=3x2y-[5xy2+2x2y-1+x2y]+6xy2
=3x2y-5xy2-3x2y+1+6xy2
=xy2+1,
当x=-2,y=

1
2
时,原式=-2×(
1
2
2+1=
1
2