# How do you find the sum or difference of (z^2+z)+(z^2-11)?

$2 {z}^{2} + z - 11$

#### Explanation:

$\left({z}^{2} + z\right) + \left({z}^{2} - 11\right)$

The hang up here appears to be what to do with the brackets. It can be thought of that each bracket has a $+ 1$ that is being distributed through each of them, and so that will look like:

color(red)(1)(z^2+z)+color(red)(1)(z^2-11))

$\textcolor{red}{1} \left({z}^{2}\right) + \textcolor{red}{1} \left(z\right) + \textcolor{red}{1} \left({z}^{2}\right) - \textcolor{red}{1} \left(11\right)$

${z}^{2} + z + {z}^{2} - 11$

And we can now combine like terms:

$2 {z}^{2} + z - 11$