Question 634283
={{{ ((x^2-y^2)/(x+y)^2)((x+y)/(x-y))}}}
={{{ ((x-y)(x+y)/(x+y)(x+y))((x+y)/(x-y))}}}
={{{ (cross((x-y)(x+y))/cross((x+y)(x+y)))(cross((x+y))/cross((x-y)))}}}
={{{1}}}