化简:1/2x-1/(x+y).[x2-y2+(x+y)/2x
已知[(x2+y2)-(x-y)2+2y(x-y)]÷4y=1,求4x/4x2-4y2-1/2x+y的值,
x2-x-y2-y 解法:=(x2-y2)-(x+y) =(x+y)(x-y)-(x+y) =(x+y)(x-y-1)
2x2+xy-3y2+x+4y-1因式分解
化简x2+2x+1分之x2-y2÷x+1分之x-y
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2的值
已知x2-4x-1=0,求代数式(2x-3)2-(x+y)(x-y)-y2的值
已知实数x,y满足x2+y2=1,求y+2x+1
若x2-2xy-y2-x+Y-1=0 求x-y的值
(x+y)(x+y+1)=0 求x2+y2+2xy的值
x(x-1)-(x2-y)=-3,求x2-y2-2xy的值
x(x-1)-(x2-y)=-3,求x2+y2-2xy的值
已知x(x-1)-(x2-y)=-3,求x2+y2-2xy的值