x(x-1)-(x^2-y)=-3.求x^2+y^2-2xy的值.[(2a+b)(2a-b)-(2a-b)^2+2b(a-b)]/4b,其中a=2,b=1.

初中数学X(X=1)-(X*X-Y)=-3.求(X*X+Y)/2+XY的值 1.(x-2y)(x+2y)-(x平方+y)(x平方-y) 2.(2x-y)(y+2x)-(2y+x)(2y-x)3.已知：x+y=6,x平方-y平方=48,求x,y的值4.x平方-2x分之x+2 -- x平方-4x+4分之x-1 已知x(x-1)-(x^2-y)=-3.求x^2+y^2-2xy y=(2x*x-2x+3)/(x*x-x+1),求值域? 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 y=x^x的导函数是：y'=x^x(Inx+1)我知道怎样求.但为什么不可以这样求.y=x^x=x*x*x*x*x*x*...*x(x个x) 则y'=(x')*x^(x-1)+x*(x')*x^(x-2)+.=x^x x+y=1,xy=-1/2,求x(x+y)(x-y)-x(x+y)2 求值域 1,y=(x+2)/(x*x+3x+6) 2,y=3x/(x*x+4) x+2y=2x+y+1=7x-y 求：2x-y? (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 若x*x+y*y=x+y-1/2,求x,y的值如题 求y =2^x -1/x+1在x 求反函数y=x^2-2x,x>1 求y=(5x-1)/(4x+2) (x y=x*x-2x+1求导数 y=(X+1)(X+2)(X+3)求导数 y=x+1/x(x>2)值域怎么求