(-2xy²)(3x²y)²=
x-y/x²÷x²-2xy+y²/xy*(xy-x²)
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
求3x²y-2xy²+2(xy-二分之三x²y)-xy+3xy²的值,其中x=3
计算 2xy[4x²y²-3y(xy+x²y)-xy²]
已知x/2=y/3(xy≠0),求x²-2xy-3y²/x²-6xy-7y²的值
-2y³+(3xy²-x²y)-2(xy²-y³)
化简(3X²-XY+Y²)-5(X²-XY+2Y²)
计算:(-7x²y)(2x²y-3xy³+xy)
2x²-3xy=y²=0(x,y不得o)求x/y+y/x
(xy-2y)(xy+2y)-(x-y)²-x²y² 其中x=5/2 y=- 3/5 先化
去括号:1/2(2X²Y-3XY²+4XY-X²Y²)=?
已知:x²-xy=9,xy-y²=5,则x²-2xy+y²=(),3x²