Find an exponential function of the form

Question

f(x) = ba^x that has the given y-intercept and passes through the point P.

y-intercept 4; P(2, 1)

Answer 1

a^x always passes through (0,1), so
f(x) = 4a^x

1 = 4a^2
a = 1/2

f(x) = 4 * (1/2)^x