若X^2-4y^2=-15,x+2y=3,求x、y值

已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y/2x-y的值 若x-y/x+y=5,求x-y/2x+2y+5x+5y/3x-3y的值 若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值 已知2x+2y=-8,4x+y=15求（x-y)^-(3x+2y)^ 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y* 已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-( 若X,Y互为相反数,且(X+Y+3)(X-Y-2)=0,求X,Y的值? 若2x-3y=0,求5x+4y/3x-2y 已知4x-2y=0,求x-y/3x+2y的值