-x+y-2=0当y=0x=?x=0y=?

当x、y满足x>=0,y>=x,2x+y+k 当实数x,y,满足约束条件{x>0 y>=x 2x+y+k -x+y-2=0当y=0x=?x=0y=? 当x,y满足条件x>=0,y 线性规划 当x.y满足x>=0,y （x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 如果y是奇函数,当x>0时,y=2x-3,当x x*x+2x+y*y-4y+5=0 x= y= (X,Y) f(x,y)={12y^2,0 已知x>0,Y>0,如何证x^2/y+y^2/x>=x+y 设Z=X+Y,其中X,Y满足X+2Y>=0,X-Y 当 x-2 的绝对值 + y+2的绝对值 =0,求x、y的值,并求x+y,xy,x-y,y分之x的值. y=2^x,y=log2x,y=x*2这三个函数,当0 y=2*x,y=log2x,y=x*2这三个函数,当0 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 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