(5x²-3y²)-[(5x²-2xy-y²)-(x²-2xy-y
-3(xy-2x²)-[y²-(5xy-4x²)+2xy]
化简(3X²-XY+Y²)-5(X²-XY+2Y²)
x-y/x²÷x²-2xy+y²/xy*(xy-x²)
1/x+1/y=5,求2x-3xy+2y/x²+xy+y的值
x²/xy-x/y
计算:(xy-x²)×x-y/xy
计算:x²+2xy+y²/xy-y².x²-2xy+y²/xy+y
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
(2x²y-3xy²)-3(x²y-2xy²)+2(x²y-4xy
先化简,再求值:{xy(x²-3y)+3xy²}(-2xy)+x³y²(2x-y
已知x+y=3 xy=-5 求x设abc=1 求x²+3xy+2y²/x²y+2xy
计算:x²y-(2xy²-5x²y)+3xy²-y³