3x^2+4xy--4y^2=0 (x≠0,y≠0),求9x^2-3xy∕18x^2+y^2的值

已知x-y=4xy且xy≠0,求代数式-x-2xy+y分之2x+3xy-2y的值 （-3x^y+2xy)-( )=4x^+xy X×X-2XY-Y×Y+2X-2Y+2=02X×2X-4XY-2Y×2Y+3X-3Y+4=0X×X+2XY+Y×Y+X+Y-56=0X×X-2XY+Y×Y-X+Y-12=0X×X-3XY+Y×Y=-13X×3X-XY+3Y×3Y=13 两个在一起的方程之间有所联系（要求一步一步写出来） 当x-y=2xy时,求4x-3xy-4y/xy 已知/X-Y-1/+(XY+3)的平方=0,求(-2XY+2X+3Y)-(3XY+2Y-2X)-(X+4Y+XY)的值!已知/X-Y-1/+(XY+3)的平方=0,求(-2XY+2X+3Y)-(3XY+2Y-2X)-(X+4Y+XY)的值急! 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) 已知x^2+3xy-4y^2=0(y≠0),求x-y/x+y的值.已知x^2+3xy-4y^2=0(y≠0),求x-y/x+y的值. 已知（x+2）^2+|x+y+5|=0,求3x^2y-[2x^2y-(2xy-x^2y)-4x^2]-xy 已知：（x+2)²+|x+y-2|=0,求3x²y+{-2x²y-[-2xy+(x²y-4x²）]-xy} 已知2x²-3y²=xy,(xy≠0),求值（4xy-x²）／(xy+2y²)的值 已知x,y>0 2x+y+3=xy 求5x+4y最小值 已知2x+3y=0,求代数式1.5x+4y/3x-2y 2.x²+xy-y²/x²-xy+y² 若|x-3|+（y+2）=0,则（x-y+4xy/x-y）（x+y-4xy/x+y）的值是 若|x-3|+（y+2）²=0,则（x-y+4xy/x-y）（x+y-4xy/x+y）的值是 诺x+y=6,xy=4 求(5x-4y-3xy)-(8x-y+2xy) 已知x-y=4xy,求2x+3xy-2y/x-2xy-y的值 x-y=4xy,试求2x+3xy-2y/x-2xy-y