#### Answer

$\frac{2}{3}$

#### Work Step by Step

We are given that $f(x)=\frac{2}{3}x+4$.
Two points are needed to calculate the slope of a line. We can calculate the value of its intercepts to find two points.
If $x=0$, $f(0)=\frac{2}{3}\times0+4=4$.
If $y=0$, $0=\frac{2}{3}x+4$.
Subtract 4 from both sides.
$-4=\frac{2}{3}x$.
Multiply both sides by $\frac{3}{2}$.
$x=-6$
Therefore, (-6,0) and (0,4) are both points on this line.
We can use the slope formula to calculate the line.
$m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}$
$m=\frac{4-0}{0-(-6)}=\frac{4}{6}=\frac{2}{3}$