55=25x+(25^2)/2y 24=15x+(15^2)/2y
x,y属于R*,且x+y=1,求证:(1)(x+1/x)(y+1/y)≥25/4 (2)(x+1/x)^2+(y+1/y
[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013
已知x.x+y.y+8x+6y+25=0,求代数式(x.x-4y.y)/(x.x+4xy+4y.y)-x/(x+2y)的
用加减法解下列方程组:{x+2y=9 3x-2y=1 {5x+2y=25 3x+4y=15 {3x+2y=6 3x-2y
2(x+y) 3x+3y=24 x+y/2x x y/2y= 1
已知2/x+2/y=根号24,求 x/y(x-y) - y/x(x-y)的值
已知2/x 2/y=根号24,求 x/y(x-y) - y/x(x-y)的值
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
1,{3x+2y=13 {5x-2y=11 ,2,{5x+2y=25 {3x+4y=15
1,{3x+2y=13 2,{5x+2y=25 {5x-2y=11 {3x+4y=15
y'-2y=(e^x)-x