Question

A 2-column table has 5 rows. The first column is labeled x with entries negative 2, negative 1, 0, 1, 2. The second column is labeled f (x) with entries 16, 8, 4, 2, 1.
Which exponential function is represented by the values in the table?

f(x) = One-half(4)x
f(x) = 4(4)x
f(x) = 4(one-half) Superscript x
f(x) = One-half (one-half) superscript x

Answer 1

Use f(0)=4, so the form f(x)=A·b^x gives A=4. Then f(1)=2 = 4·b, so b = 1/2. Thus

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