The root of polynomial $ p(b) $ is:
$$ \begin{aligned}b &= 0 \end{aligned} $$Step 1:
Get rid of fractions by multipling equation by $ \color{blue}{ 2 } $.
$$ \begin{aligned} -\frac{1}{2}b-\frac{3}{2}b-\frac{5}{2}b & = 0 ~~~ / \cdot \color{blue}{ 2 } \\[1 em] -b-3b-5b & = 0 \end{aligned} $$Step 2:
Combine like terms:
$$ \color{blue}{-b} \color{red}{-3b} \color{red}{-5b} = \color{red}{-9b} $$Step 3:
$$ \begin{aligned} -9b & = 0 \\[1 em] x & = 0 \end{aligned} $$