Question

This table shows several values of an exponential function.
x f(x)
2
–
16
3
–
32
4
–
64
5
–
128
Write an equation for the function in the form f(x)=a(b)x.
Use whole numbers, decimals, or simplified fractions for the values of a and b.
f(x)=

Answer 1

f(x) = -4(2)^x

Reason: b = f(3)/f(2) = (-32)/(-16) = 2, and then a = f(2)/b^2 = -16/4 = -4.