x^2+y^2+16x-4y+68=0,则x+y=?
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值?
设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于
若3x-4y=0,则x/y=______,(x-y)/y=______,(3x+2y)/(2x+3y)=_____.
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*
x*x+4y*y+2x*x-4y+2=0求根号下5x*x+16y*y的值快啊
x平方-4x+2y+6y+13=0则x= y=?
已知x²+4x+y²-2y+5=0,则x+y=
若|x+2y-1|+y²+4y+4=0,求(2x-y)²-2(2x-y)(x+2y)+(x+2y)&
[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013
已知x^2+4y^2-4x+4y+5=0,求(y^4-x^4)/(y-2x)(x+y)*2x-y
若3x-5y=0,则x+y/x=(),x-y/y=(),2x-3y/2x+3y=( )