已知:x.y满足方程组{x+2y=5 2x-y=-1 求x3-xy2/x+y *x2-2xy+y2/x -2y+2/y-

正整数x,y满足x2-y2=2xy,求x-y/x+y的值 整数x,y满足x2-y2=2xy,求x-y/x+y的值 已知实数x,y满足(x2)+(y2)-xy+2x-y+1=0,求x,y的值 已知实数x、y满足X2+y2-xy+2x-y+1=0,试求x、y的值 已知实数x、y满足2x2-7xy+3y2=0,求x：y 已知实数x,y满足方程组{x+xy+y=2+3倍根号2 {x2+y2=6 求(x+y+1)的绝对值 已知实数x,y满足方程组x+xy+y=2+3根号2和x2+y2=6.求|x+y+1|的值. 1.已知正数x,y满足x2-y2=2xy,求(x-y)/(x+y)的值 正数xy满足x2-y2=2xy,求x+y分之x-y的值 已知x2+y2-2x+4y+5=0,求(x^4-y^4)/(2x^2+xy-y^2)·[(2x-y)/(xy-y^2)] 已知x+y+z=1,x2+y2+z2=2,x3+y3+z3=3,求xy(x+y)+yz(y+z)+zx(z+x)的值 已知(x+3)2+▕x-y+10▏=0求代数式5x2y-【2x2-（3xy-xy2）-3x2】-2xy2-y2的值.