已知x²-3y²=2xy（x>0,y>0)

已知X²-5XY+6Y²=0,求(X²+3XY)\2Y²的值 已知3x²+xy-2y²=0(x≠0,y≠0),求x/y-y/x-x²+y²/x |x+2y+3|+(2x+y)²=0求x²-xy+y² 已知x²+y²=3xy且xy≠0,求x²y－²+x－²y²的 已知2x²-3y²=xy,(xy≠0),求值（4xy-x²）／(xy+2y²)的 已知|x+2|+(y+1²=0,求x²+(2xy-3y²)-2(x²+xy-2y 已知3x+2y=0,求代数式(x²+xy-y²)÷(x²-xy+y²)的值. 已知2x+3y=0,求代数式1.5x+4y/3x-2y 2.x²+xy-y²/x²-xy+ 已知（x+2）²+|x+y+5|=0,求3x²y+{-2x²y-[-2xy+（x² 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 已知x²-2xy=3xy-6y² ,求x/y(y不等于0)的值