What does the transformation $f(x) \mapsto f\left(\frac{1}{7} x\right)$ do to the graph of $f(x)$ ? reflects it across the $x$-axis shrinks it horizontally reflects it across the $y$-axis stretches it horizontally

Step 1 ：The transformation \(f(x) \mapsto f\left(\frac{1}{7} x\right)\) means that every \(x\) value in the original function \(f(x)\) is replaced by \(\frac{1}{7}x\).

Step 2 ：This has the effect of stretching the graph of \(f(x)\) horizontally by a factor of 7.

Step 3 ：This is because for any given \(y\) value, the corresponding \(x\) value in the transformed function is 7 times larger than in the original function.

Step 4 ：For example, if \(f(1) = 2\) in the original function, then in the transformed function, \(f(7) = 2\).

Step 5 ：So, the graph of the function is stretched horizontally.