x^2-y^2=44,x-y=11,则x+y=_____
若3x-4y=0,则x/y=______,(x-y)/y=______,(3x+2y)/(2x+3y)=_____.
若x+y=9,xy=20则 x^2+y^2=_____, (x-y)^2=_____
[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013
已知二元一次方程组:2x+y=7,x+2y=8则x-y=_____,x+y=_____.
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
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)
若x-y=2,x的平方-y的平方=1,则x+y=_____.
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
已知|2x-y|+(x-2y+3)的平方=0,则(x-y)的2011次方=_____.
设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于