We make the composition of both functions:
f (x) = x ^ 2-1
g (x) = 2x-3
Then:
f (g (x)) = (2x-3) ^ 2-1
Rewriting:
f (g (x)) = 4x ^ 2-12x + 8
The domain of this function is all real numbers.
Equivalently
x: (-inf, inf)
answer:
x: (-inf, inf)
option 1.