-3(xy-2x²)-[y²-(5xy-4x²)+2xy]
-3(xy-2x²)-[y²-(5xy-4x²)+2xy]
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
(2x²y-3xy²)-3(x²y-2xy²)+2(x²y-4xy
已知(x+1)²+|y-1|=0,求2(xy-5xy²)-(3xy²-xy)得值
化简4xy-3y²-3x²+xy-3xy-2x²+x²-2y²
x-y/x²÷x²-2xy+y²/xy*(xy-x²)
计算 2xy[4x²y²-3y(xy+x²y)-xy²]
已知x:y=3:2,求(x²+3xy)/(xy+2xy)
-3(2x²-xy)+4(x²+xy-6)
化简(3X²-XY+Y²)-5(X²-XY+2Y²)
-4x²y-8xy²+2x²y-3xy²
化简并求值 xy-2{xy-[3x²y-(xy²+0.5xy)]+4x²y},其中x=1,