This is the problem that I was working on. Initially, I thought that the answer would be 1/a

^{2} + b

^{2}

Do you under stand the following):

(a + b) * ( x + y) ..................using distributive law of multiplication, we get:

= a * (x + y) + b * (x + y) ..................using distributive law of multiplication again, we get:

= a*x + a*y + b*x + b*y

Follow the same steps - replace (x+y) by (a+b)

(a + b) * ( a + b)

= a*(a+b) + b*(a+b) .....................continue..........