1/a +1/b ----------- a - 1/b tolong di bantu

1/a +1/b
-----------
a - 1/b

= b/ab + a/ab
-------------------
ab/b - 1/b

= b+a / ab
----------------
ab - 1 / b

= b+a / ab × b / ab - 1

= (b + a) b
--------------
ab (ab - 1)

= b (a + b)
------------------
a^2 b^2 - ab

= b (a + b)
---------------
b (a^2 b - a)

= (a + b)
-------------
a^2b - a