(2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy&#

来源：学生作业帮编辑：搜狗做题网作业帮分类：数学作业时间：2024/04/28 00:37:01

(2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy²）,其中x=-1,y=2.
先化简,后求值,

(2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy²）
=2x²y-3xy²-3x²y+6xy²+2x²y-8xy²
=x²y-5xy²
=xy(x-5y)
将x=-1,y=2.代入得
原式=-2×(-1-10)=22

3x²y+xy²-[2xy²-4x²y+（x²y-2xy²） (2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy&# -3(xy-2x²)-[y²-(5xy-4x²)+2xy] 计算 2xy[4x²y²-3y（xy+x²y）-xy²] 化简4xy-3y²-3x²+xy-3xy-2x²+x²-2y² x-y/x²÷x²-2xy+y²/xy*（xy-x²）先化简,再求值:{xy(x²-3y)+3xy²}(-2xy)+x³y²(2x-y -4x²y-8xy²+2x²y-3xy² 计算：x²+2xy+y²/xy-y².x²-2xy+y²/xy+y&# 已知x:y=3:2,求(x²+3xy)/(xy+2xy) 下列多项式:(1)x²+xy-y²;(2)-x²+2xy-y²;(3)xy+x& 已知x/y=3,求(x²+2xy-3xy²)/(x²-xy+y²)