Sorry i wrote question down wrong ...

If f (x) = x+7 and g (x) = 1/x-13, what is the domain of (f*g) (x) ?

" * " means times or multiplication

F (x) = x+7

g (x) = 1 / (x-13)

Domain (f*g) (x) = ?

(f*g) (x) = f (x) * g (x) = (x+7) * [1 / (x-13) ]→ (f*g) (x) = (x+7) / (x-13)

(f*g) (x) is a rational function, then the denominator must be different of zero:

x-13 ≠ 0

x-13 + 13≠ 0+13

x ≠ 13

Then:

Domain (f*g) (x) = R-{13} = (-Infinite, 13) U (13, Infinite)

R: All the real numbers