What is the domain of the function$$\ell(y) = \frac{1}{(y-2)+(y-8)}~?$$Express your answer in interval notation.
We need y not equal to 2, and y not equal to 8, so the domain is (-inf,2) U (2,8) U (8,inf).
The denominator simplifies to
2y -10
Since this cannot = 0 then y = 5 is NOT in the domain
So
domain = (-inf , 5) U ( 5 ,inf )
+248 
