Hi there! Your answer is all real numbers.
Please see an explanation for a clear understanding to your problem.
Any questions about my answer and explanation can be asked through comments! :)
Step-by-step explanation:
[tex] \large \boxed{ \sf{domain = set \: \: of \: \: all \: \: x - values}}[/tex]
Remember, domain is set of all x-values. Therefore, we can cancel b choice because y>0 is range, not domain.
Given the exponential function
[tex] \large{y = {a}^{x} } \: \: \large({x \in \R}) \: \: \large({y \in \R^{ + } })[/tex]
This is the define of Exponential Function where x is all real numbers and y is all real positive number.
Hence, the define of exponential function proves that x must be all set of real numbers.
