(5x²-3y²)-[﹙5x²-2xy-y²﹚-﹙x²-2xy+3y&
已知:(x+2)²+|x+y-10|=0,求3x²y-[5x²y-﹙2xy-x²
先化简再求值xy﹙x²+y﹚-y²﹙xy+2x﹚-3xy²,其中x=5,y=﹣1
已知x=3 y=1\3,求3x²y-[2xy²-2﹙xy-3\2x²y﹚+xy]+3xy&
(3x+2y)(9x²-6xy+4y²﹚
[xy(x²-3y)+3xy²]﹙﹣2xy﹚+x³y²﹙2x-y﹚ 其中x=﹣1
化简(3X²-XY+Y²)-5(X²-XY+2Y²)
已知x-5y=0,求分式x²-2xy+y²/3x+y × (y-x)的值
2x²-5x+x²+4x-3x² -3x²y+2xy²+3xy
已知:x²+y²-2x+4y+5=0,求﹙y/x²-xy﹚-﹙x/xy-x²﹚的
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
-3(xy-2x²)-[y²-(5xy-4x²)+2xy]
x-y/x²÷x²-2xy+y²/xy*(xy-x²)