# How do you find the sum or difference of (2a-4a^2+1)-(5a^2-2a-6)?

Dec 18, 2016

$- 9 {a}^{2} + 4 a + 7$

#### Explanation:

First, expand the terms within parenthesis paying close attentions to the signs inside and out side the parenthesis:

$2 a - 4 {a}^{2} + 1 - 5 {a}^{2} + 2 a + 6$

Now, group like terms:

$- 4 {a}^{2} - 5 {a}^{2} + 2 a + 2 a + 1 + 6$

Next combine the like terms:

$\left(- 4 - 5\right) {a}^{2} + \left(2 + 2\right) a + 7$

$- 9 {a}^{2} + 4 a + 7$