5ab part 4A + 4B times the square of A-B part 15A square B

5ab part 4A + 4B times the square of A-B part 15A square B

The original formula = [4 (a + b) / (5ab)] × (15a & sup2; b) / [(a + b) (a-b)] is reduced to 5ab and (a + b)
=4×3a/(a-b)
=12a/(a-b)