Question 550678
={{{2a/(a+b)^2(a-b)+2b/(a+b)(a-b)^2-1/(a+b)^2-1/(a-b)^2}}}
Take LCD 
={{{(2a(a-b)+2b(a+b)-(a-b)^2-(a+b)^2)/(a+b)^2(a-b)^2}}}
={{{(2a^2-2ab+2ab+2b^2-(a^2-2ab+b^2)-(a^2+2ab+b^2))/(a+b)^2(a-b)^2}}}
={{{(2a^2-cross(2ab)+cross(2ab)+2b^2-(a^2-2ab+b^2)-(a^2+2ab+b^2))/(a+b)^2(a-b)^2}}}
={{{(2a^2+2b^2-(a^2-2ab+b^2)-(a^2+2ab+b^2))/(a+b)^2(a-b)^2}}}
={{{(2a^2+2b^2-a^2+2ab-b^2-a^2-2ab-b^2)/(a+b)^2(a-b)^2}}}
={{{(2a^2-2a^2+2b^2-2b^2+2ab-2ab)/(a+b)^2(a-b)^2}}}
={{{(cross(2a^2)-cross(2a^2)+cross(2b^2)-cross(2b^2)+cross(2ab)-cross(2ab))/(a+b)^2(a-b)^2}}}
={{{1/(a+b)^2(a-b)^2}}}