# How do you solve and write the following in interval notation: |2x + 9 |>= 15?

$x \ge 3$ or $x \le - 12$; Expressed in interval notation: $\left(- \infty , - 12\right] \cup \left[3 , \infty\right)$
$| 2 x + 9 | \ge 15 \therefore 2 x + 9 \ge 15 \mathmr{and} 2 x \ge 6 \mathmr{and} x \ge 3$ OR
$| 2 x + 9 | \ge 15 \therefore 2 x + 9 \le - 15 \mathmr{and} 2 x \le - 24 \mathmr{and} x \le - 12$
Expressed in interval notation: $\left(- \infty , - 12\right] \cup \left[3 , \infty\right)$[Ans]