Answer
$ b\gt 19$.
The graph is shown below.
Work Step by Step
The given inequality is
$\Rightarrow 15\lt b-4$
Add $4$ to each side.
$\Rightarrow 15+4\lt b-4+4$
Simplify.
$\Rightarrow 19\lt b$
Hence, the solution is $ b\gt 19$.
Use an open circle because $19$ is not a solution.
Shade the number line on the right side.
