Chapter 4 - Polynomial and Rational Functions - 4.3 The Graph of a Rational Function - 4.3 Assess Your Understanding - Page 213: 71

$f(x)=|x|-4$.

RECALL: The graph of $y=f(x)+k$ involves a vertical shift of $|k|$ units (upward when $k \gt 0$, downward when $k\lt0$) of the parent function $f(x)$. Use the rule above to find the equation of the given graph. Shifting the graph of $y=|x|$ vertically $4$ units down means $k=-4$ therefore the equation of the resulting function is $f(x)=y-4\\ f(x)=|x|-4$