若X^2-y^2=48,x+y=4,则x=?,y=?
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于
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*
若3x-4y=0,则x/y=______,(x-y)/y=______,(3x+2y)/(2x+3y)=_____.
[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013
若5x+3y=3x+4y=x+2y+6,则x+y=___
若x/y=4/3 则3x+2y/2x-5y=
若|x+y+4|=-(x-y)4次方,则(-2y)平方x=
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20
{(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20