Question

$5x - 4 = 21$

Explanation:

Step1: Add 4 to both sides

$5x - 4 + 4 = 21 + 4$
$5x = 25$

Step2: Divide by 5 on both sides

$\frac{5x}{5} = \frac{25}{5}$
$x = 5$

Answer:

$x=5$