若2x-y=2y-x=15,则x-y=________.
若2x-y=2y-x=15,则x-y=________.
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于
已知点(x,y)满足|x|+|y|=1,则(x-1)^2+y^2 的最大值为________
[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013
若3x-5y=0,则x+y/x=(),x-y/y=(),2x-3y/2x+3y=( )
若全集I={(x,y)|x,y∈R},集合M={(x,y)|(y-3)/(x-2)},N{(x,y)|y=x=1},则(
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)
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
y'-2y=(e^x)-x
y'+2y/x=x通解