# How do you simplify (3x ^ { 2} + 5x - 1) + ( 3x ^ { 2} + 3x + 15) - ( 6x ^ { 2} - 13)?

May 10, 2018

Since no terms within each set of parentheses are like terms, we can simplify this without the parentheses.

Note: since there is a - before $\left(6 {x}^{2} - 13\right)$, we multiply all terms inside it by -1, thus $- 6 {x}^{2} + 13$

$3 {x}^{2} + 5 x - 1 + 3 {x}^{2} + 3 x + 15 - 6 {x}^{2} + 13$

Now group the like terms, and simplify.
$3 {x}^{2} + 3 {x}^{2} - 6 {x}^{2} + 5 x + 3 x - 1 + 15 + 13$

$8 x + 27$

May 10, 2018

$8 x + 27$

#### Explanation:

$3 {x}^{2} + 5 x - 1$
$\underline{3 {x}^{2} + 3 x + 15 \leftarrow \text{ Add}}$
$6 {x}^{2} + 8 x + 14$
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

$6 {x}^{2} + 8 x + 14$
$\underline{6 {x}^{2} + 0 x - 13 \leftarrow \text{ Subtract}}$
$0 {x}^{2} + 8 x + 27$

$\textcolor{w h i t e}{}$

Answer $\to 8 x + 27$