# How do you subtract (- 3x^{2} + 6x - 1) - ( - 5x^{2} + 4x + 2)?

Sep 16, 2016

$2 {x}^{2} + 2 x - 3$

#### Explanation:

We have: $\left(- 3 {x}^{2} + 6 x - 1\right) - \left(- 5 {x}^{2} + 4 x + 2\right)$

$= - 3 {x}^{2} + 6 x - 1 + 5 {x}^{2} - 4 x - 2$

Let's group the like terms:

$= \left(- 3 + 5\right) {x}^{2} + \left(6 - 4\right) x + \left(- 1 - 2\right)$

$= 2 {x}^{2} + 2 x - 3$

Sep 16, 2016

$2 {x}^{2} + 2 x - 3$

#### Explanation:

Subtracting a number or expression is the same as adding on its inverse.

The effect of the minus sign in front of the bracket is to change the signs in the bracket.

$\left(- 3 {x}^{2} + 6 x - 1\right) \textcolor{b l u e}{- \left(- 5 {x}^{2} + 4 x + 2\right)}$

=$- 3 {x}^{2} + 6 x - 1 + \textcolor{b l u e}{5 {x}^{2} - 4 x - 2} \text{ } \leftarrow$ collect like terms.

= $2 {x}^{2} + 2 x - 3$