Question

The function g(x)=8(4x) is reflected across the x-axis to create f(x).

On a coordinate plane, 2 exponential functions are shown. Function f (x) approaches y = 0 in quadrant 3 and decreases into quadrant 4. It crosses the y-axis at (0, negative 8). Function g (x) approaches y = 0 in quadrant 2 and increases into quadrant 1. It crosses the y-axis at (0, 8).

What is the equation of f(x)?

f(x)=8(4)x
f(x)=−8(4)x
f(x)=8
f(x)=−8

Answer 1

f(x) = −8(4^x)

Reason: reflecting g(x)=8(4^x) across the x-axis multiplies the output by −1, so f(x)=−g(x)=−8(4^x). This gives f(0)=−8 and the graph approaches 0 from below.