Answer:
-2b/(a-b)
Step-by-step explanation:
1− (a+b/a−b)
We need to get a common denominator of a-b
1 = (a-b)/(a-b)
Replace 1 with (a-b)/(a-b)
(a-b)/(a-b) - (a+b)/(a-b)
Put over the common denominator
(a-b) - (a+b)
-----------------
(a-b)
Distribute the minus sign.
(a-b) - a-b)
-----------------
(a-b)
a-a-b-b
---------------
a-b
-2b
----------
a-b
