# How do you find the sum or difference of (cd^2+2cd-4)+(-6+4cd-2cd^2)?

Dec 21, 2016

$- c {d}^{2} + 6 c d - 10$

#### Explanation:

First, you need to expand the terms within parenthesis. Pay special attention to the signs of each term:

$c {d}^{2} + 2 c d - 4 + \left(- 6\right) + 4 c d + \left(- 2 c {d}^{2}\right)$

$c {d}^{2} + 2 c d - 4 - 6 + 4 c d - 2 c {d}^{2}$

Next we can group like terms:

$c {d}^{2} - 2 c {d}^{2} + 2 c d + 4 c d - 4 - 6$

Then finally, we can combine like terms:

$\left(1 - 2\right) c {d}^{2} + \left(2 + 4\right) c d - 10$

$- 1 c {d}^{2} + 6 c d - 10$

$- c {d}^{2} + 6 c d - 10$