The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0\\[1 em]x_2 &= -\frac{ 3 }{ 2 } \end{aligned} $$Step 1:
Factor out $ \color{blue}{ x^5 }$ from $ 2x^6+3x^5 $ and solve two separate equations:
$$ \begin{aligned} 2x^6+3x^5 & = 0\\[1 em] \color{blue}{ x^5 }\cdot ( 2x+3 ) & = 0 \\[1 em] \color{blue}{ x^5 = 0} ~~ \text{or} ~~ 2x+3 & = 0 \end{aligned} $$One solution is $ \color{blue}{ x = 0 } $. Use second equation to find the remaining roots.
Step 2:
To find the last zero, solve equation $ 2x+3 = 0 $
$$ \begin{aligned} 2x+3 & = 0 \\[1 em] 2 \cdot x & = -3 \\[1 em] x & = - \frac{ 3 }{ 2 } \end{aligned} $$