x²y²-4xy²+4y²-9
(-x-2y)(x²-2xy+4y²)
化简(x²y-4y²)/(x²+4xy+4y²)*[(4xy)/(x-2y)+x
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
(2x²y-3xy²)-3(x²y-2xy²)+2(x²y-4xy
因式分解:x²-y²+4xy
已知x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
因式分解:4x²y+4xy²+xy²
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
x²/xy-x/y
计算:(xy-x²)×x-y/xy
因式分解,x²y²-4+xy²-2y.
计算 2xy[4x²y²-3y(xy+x²y)-xy²]