Answer
(a) shrink $f(x)$ horizontally by a factor of $\frac{1}{4}$
(b) stretch $f(x)$ horizontally by a factor of 4
Work Step by Step
(a) We can obtain $f(4x)$ by shrinking $f(x)$ horizontally by a factor of $\frac{1}{4}$.
(b) We can obtain $f(\frac{1}{4}x)$ by stretching $f(x)$ horizontally by a factor of 4.
