x-y=9,x*y=5,求x^2+y^2的值

已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 求(X+Y)(X-Y)(X²+Y²),X=5 Y=2, (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 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*y)的值 5x*2y=（x-y）^2 x+9y=55 求x、y x-y=9,x*y=5,求x^2+y^2的值 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 已知3x =2y 求x/x+y+y/x-y-y²/x²-y² y=2x*arctan(y/x),求y‘’ 5X+Y=3 X+5Y=2 求x和y.5X+Y=3X+5Y=2求x和y. x*x+y*y-2x+4y+5=0求x, 已知:3x-5y=0,求x/y,x-y/y,x-y/x 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值