(X+Y)(X+Y+12)=15,则X+Y=

已知实数x,y满足|x|+x+y=10、x+|y|-y=12,则x+y的值? (x*x+y*y)(x*x+y*y)-(x*x+y*y)=12 求x*x+y*y等于多少 1.已知1/x+1/y=-1/x+y,则y/x+x/y=? 已知x/5=y/3,则(x/x+y)+(y/x-y)-(yxy/xxx-yxy) 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 二元函数f(x,y)=x+y/x-y,求f(y/x,x/y) 实数x，y满足tanx=x，tany=y，且|x|≠|y|，则sin(x+y)x+y−sin(x−y)x−y 现规定一种新运算：x*y=(x+y)-(x-y),其中x,y为有理数,则x*y+(x+y)*(x-y)等于多少 [x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? X.Y为自然数,X(X-Y)-Y(Y-X)=12,求X.Y的值 x,y都是自然数,且x(x-y)-y(y-x)=12,求x+y-xy的值