1、x+y=22 2、x+y=9
已知4x=9y求(1)x+y/y (2)y-x/2x
9y=3x-(x-1),4(x+y)-(2x+4)=8y
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
{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
x+y=3 x+2y=9 3/x+1=y y-x=3 y=2x-3 y-3x=1 2(x+1)-y=6 7x-5y=-9
Y=1/X X^2+Y^2=9 Y=|-2x| X=-3|sin y|
y=(x^2+x)/(x+1)
2(x+y) 3x+3y=24 x+y/2x x y/2y= 1
3x=2y+1;x=9y;求x,y的值?
设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于