# How do you solve abs(4x+5)>=13?

May 13, 2017

See a solution process below:

#### Explanation:

The absolute value function takes any negative or positive term and transforms it to its positive form. Therefore, we must solve the term within the absolute value function for both its negative and positive equivalent.

$- 13 \ge 4 x + 5 \ge 13$

First, subtract $\textcolor{red}{5}$ from each of the segments of the system of inequalities to isolate the $x$ term while keeping the system balanced:

$- 13 - \textcolor{red}{5} \ge 4 x + 5 - \textcolor{red}{5} \ge 13 - \textcolor{red}{5}$

$- 18 \ge 4 x + 0 \ge 8$

$- 18 \ge 4 x \ge 8$

Now, divide each segment by $\textcolor{red}{4}$ to solve for $x$ while keeping the equation balanced:

$- \frac{18}{\textcolor{red}{4}} \ge \frac{4 x}{\textcolor{red}{4}} \ge \frac{8}{\textcolor{red}{4}}$

$- \frac{9}{2} \ge \frac{\textcolor{red}{\cancel{\textcolor{b l a c k}{4}}} x}{\cancel{\textcolor{red}{4}}} \ge 2$

$- \frac{9}{2} \ge x \ge 2$

Or

$x \le - \frac{9}{2}$ and $x \ge 2$

Or, in interval notation:

$\left(- \infty , - \frac{9}{2}\right]$ and $\left[2 , \infty\right)$