已知x-2y=3,x²-2xy+4y²=11,求①xy ②x²y-2xy²

已知x-2y=3,x²-2xy+4y²=11,求①xy ②x²y-2xy² 已知x/y=3,求x²+2xy-3y²/x²-2xy+y² 已知x/y=3,求x²+2xy-3y²/x²-xy+y²的值 问已知x²+y²=7,xy=－2,求5x²-3xy-4y²-11xy-7x&su 已知X²-5XY+6Y²=0,求(X²+3XY)\2Y²的值 已知x/y=3,求x²+2xy-3y²/x²-xy+y³的值 x/y=2,求分式x²-xy+3y²/x²+xy+6y² |x+2y+3|+(2x+y)²=0求x²-xy+y² 已知2x²+xy=10,3y²+2xy=6,求4x²+8xy+9y²的值 已知2x²+xy=10,3y²+2xy=6,求4x²+8xy+y²的值 1.已知x/y=3/4,求(7x²-3xy+2y²)/(2x²-3xy+7y²) 已知2x²-3y²=xy,(xy≠0),求值（4xy-x²）／(xy+2y²)的