# How do you solve the equation 5x+12=-3x-4?

Jan 20, 2017

$x = - 2$

#### Explanation:

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

$5 x + 3 x + 12 = \cancel{- 3 x} \cancel{+ 3 x} - 4$

$\Rightarrow 8 x + 12 = - 4$

subtract 12 from both sides.

$8 x \cancel{+ 12} \cancel{- 12} = - 4 - 12$

$\Rightarrow 8 x = - 16$

To solve for x, divide both sides by 8

$\frac{\cancel{8} x}{\cancel{8}} = \frac{- 16}{8}$

$\Rightarrow x = - 2$

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

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

$\text{left side } = \left(5 \times - 2\right) + 12 = - 10 + 12 = 2$

$\text{right side } = - \left(3 \times - 2\right) - 4 = = 6 - 4 = 2$

$\Rightarrow x = - 2 \text{ is the solution}$