0.001^x=1,(-3)^y=-1/27
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y
{3(x+y)+3(y+x)=1,3(x+y)+4(y-x)=-1
2^x=4^(y-1) 27^y=3^(x+1)求x-y
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
(3x-y)^2+(3x+y)(3x-y),x=1,y=-2
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
y'=(x-y+1)/(x+y-3)通解
2(x+y) 3x+3y=24 x+y/2x x y/2y= 1
x>1,y>0,且满足xy=x^y,x/y=x^3y,求x+y
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y