Question

已知：2X-Y等于2010,求式子（（X^2+Y^2)-(X-Y)^2+2Y(X-Y))除以4Y的值.

Answer 1

（（X^2+Y^2)-(X-Y)^2+2Y(X-Y))/4Y =（（X^2+Y^2)-(X^2-2XY+Y^2)+2Y(X-Y))/4Y =(X^2+Y^2-X^2+2XY-Y^2+2YX-2Y^2)/4Y =(4XY-2Y^2)/4Y =(2X-Y)/2 =1005