## Precalculus (6th Edition)

$\color{blue}{f(x)=9x}$
RECALL: The linear function $f(x)=ax+b$ has a slope of $a$ and a y-intercept of $(0, b)$. The given linear function has a slope of $9$ and a y-intercept of $(0, 0)$. This means that $a=9$ and $b=0$. Thus, the equation of the linear function is: $f(x) = 9x + 0 \\\color{blue}{f(x)=9x}$