# How do you solve -3( x + 4) + 15= 6- 4x?

Mar 13, 2017

$x = 3$

#### Explanation:

The first step is to distribute the bracket on the left side.

$\Rightarrow - 3 x - 12 + 15 = 6 - 4 x$

$\Rightarrow - 3 x + 3 = 6 - 4 x$

Collect terms in x on the left side and numeric values on the right side.

$- 3 x + 4 x + 3 = 6 \cancel{- 4 x} \cancel{+ 4 x}$

$\Rightarrow x + 3 = 6$

subtract 3 from both sides.

$x \cancel{+ 3} \cancel{- 3} = 6 - 3$

$\Rightarrow x = 3$

$\textcolor{b l u e}{\text{As a check}}$

Substitute this value into the equation and if the left side equals the right side then it is the solution.

$\text{left side } = - 3 \left(3 + 4\right) + 15 = \left(- 3 \times 7\right) + 15$

$\textcolor{w h i t e}{\le f t s i \mathrm{de}} = - 21 + 15 = - 6$

$\text{right side} = 6 - \left(4 \times 3\right) = 6 - 12 = - 6$

$\Rightarrow x = 3 \text{ is the solution}$