已知x(x-1)-(xx-y)=-3求xx+yy-2xy

已知x(x-1)-(xx-y)=-3求xx+yy-2xy 已知x（x+1)-(xx+y)=3,求(xx+yy)/2-xy的值 已知：3x=xx-x+1求（xxxx+xx+1）分之xx 已知xx+yy+4x-6y+13=0,求（xx-2x）/xx+3yy的值. 已知2x=3y,求xy/xx+yy-yy/xx-yy的值 x(x+1)-(xx+y)=-3,求(xx+yy)/2-xy的值 已知14(XX+YY+ZZ)=(X+2Y+3Z)^2,求X:Y:Z 已知x+1/x=3,求(xx)/(xxxx+xx+1)的值 已知XX+X+1=0,求XXX+2XX+2X+3的值 已知x/(xx+x+1)=a,求xx/(xxxx+xx+1)的值 已知(x+y)(x+y)=25,(x-y)(x-y)=9求xy与xx+yy的值 已知X*X-5X+1=0,求X*X+1/XX的值 已知XX-11X+1=0,求下列各式:(1)X+1／X(2)XX+1／XX(3)XX／XXXX+1XX-11X+1=0的意思X乘X减11X加一等于0(1)X+1／X的意思是 X加1分之X(2)XX+1／XX X的平方加1分之X的平方(3)XX／XXXX+1 X的平方分之X的四次方加1 已知xx+x-1=0,求:xx+1/xx,xxxx+1/xxxx x-y=3,(x+y)(x+y)=25,求xy/xx+yy的值? 规定X@y=Xx(X+1)x(X+2)x.x(X+y-1),如2@4=2x3x4x5已知n+1/n@3=1/575,求自然数n 一道我周报上的题目已知x*x+3x+1=0,求x*x+1/x*xx*x就是x的次方 已知x+2y-5z=3;x-2y-z=-5,求xx+yy+zz的值