已知x+y=3,x^2+y^2=5,则xy的值等于多少

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+4x+y*y-2y+5=0,则x*x+y*y=? 已知x-y=3则5(x-y)-3x+3y-2= 已知x-y=3则5(x-y)-3x+3y-2= 已知2x=3y,则y分之x=< >,y分之x+y=< >. 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 比例线段：已知x/y=2/3,则 x/x+y= ,x-y/x+y= 要过程! 已知3x =2y 求x/x+y+y/x-y-y²/x²-y² 已知|x+y-3|+(x-y)2=0则 已知:3x-5y=0,求x/y,x-y/y,x-y/x 已知f(x+y,y/x)=x^2-y^2,则f(x,y)= 已知|x|=2,|y|=3,|x+y|=-(x+y)求x-y 已知x/5=y/3,则(x/x+y)+(y/x-y)-(yxy/xxx-yxy) 1 已知1/X+1/Y=1/X+Y 则 Y/X+X/Y=2 已知1/X-1/Y=5,则3X+5XY-3Y/X-3XY-Y= 已知方程组{(X+Y)-3(X-Y)=7,2(X+Y)+(X-Y）=-7}则(X+Y)(X-Y)= 已知实数x,y满足y=x^2+5x-4,则3x-2y最大值为 已知1/x-1/y=3,则5x+3y-5y/x-2xy-y的值 已知x/1-y/1=3,则5x+xy-5y/x+2y-y的值为