# How do you factor 5z^2+10z?

$5 {z}^{2} + 10 z = \textcolor{g r e e n}{5 z \left(z + 2\right)}$
The constant parts of the terms: $5$ and $10$ have an obvious common factor of $5$.
The variable parts of the terms: ${z}^{2}$ and $10 z$ have an obvious common factor of $z$.
Therefore $5 z$ can be extracted as a common factor of the two terms.