Answer:
To simplify the given expression, you need to take commons both in upper and lower part of the fraction..
a² - ab - ac + bc
------------------------
a² + ab - ac - bc
a(a - b) -c ( a -b)
------------------------
a( a+ b) - c(a + b)
(a-b) (a-c)
--------------
(a+b) (a-c)
Now we can cancel out (a-c) from both sides..
so the result is:
(a-b)
------
(a+b)
