Answer:
Step-by-step explanation:
Any [tex]b\neq 0[/tex] raised to the 0-th power will give 1. So [tex]a=3[/tex]
Once you know that, from the passing through (2,48) you get:
[tex] 48=3b^2\\ 16=b^2 b=4 [/tex]
Notice that,even if -4 satisfies the condition, exponential functions are defined only and only if the base is positive and not equal to 1. (if the base was 1, you'd get an horizontal line, and with a negative base the function starts losing meaning in the real plane in a series of points.