# How do you combine (2x^2 + 7) - (z^2 + 1)?

Jul 30, 2015

You subtract like terms.

#### Explanation:

This expression can be written by removing the parantheses like this

$2 {x}^{2} + 7 - {z}^{2} - 1$

Finally, you can subtract like terms, which in your case are the terms that do not contain ${x}^{2}$ or ${z}^{2}$

$2 {x}^{2} - {z}^{2} + 7 - 1 = \textcolor{g r e e n}{2 {x}^{2} - {z}^{2} + 6}$