# How do you solve 1 - 4a > 21?

May 23, 2018

$a < - 5$

#### Explanation:

$\text{subtract 1 from both sides}$

$\cancel{1} \cancel{- 1} - 4 a > 21 - 1$

$- 4 a > 20$

$\text{divide both sides by } - 4$

$\textcolor{b l u e}{\text{reversing the sign as a consequence}}$

$a < - 5 \text{ is the solution}$

$a \in \left(- \infty , - 5\right) \leftarrow \textcolor{b l u e}{\text{in interval notation}}$