Question 152396
{{{(x^-2-y^-2)/(x^-1-y^-1)}}}
={{{(1/x^2-1/y^2)/(1/x-1/y)}}}
={{{((y^2-x^2)/(x^2y^2))/((y-x)/(xy))}}}
={{{((y^2-x^2)/(x^2y^2))*((xy)/(y-x))}}}
={{{(((y+x)(y-x))/(x^2y^2))*((xy)/(y-x))}}}
={{{(y+x)/(xy)}}}
={{{(x+y)/(xy)}}}