Please help me with my Pre-Cal!

Question

An exponential model y=a*b^x passes through the points (0,7) and (3,448). What are the values of a and b?

Answer 1

Just plug in the two points and solve for a and b:

y = a·b^x

Plug in (0,7):

7 = a·b⁰

7 = a (since b⁰ = 1)

Now plug in (3,448):

y = 7·b^x

448 = 7·b³

64 = b³

4 = b

y = 7·4^x