# How do you solve -21 = -r -5?

Mar 19, 2018

$r = 16$

#### Explanation:

To calculate $\left(r\right)$, we must isolate the variable onto one side:

$- 21 = - \left(r\right) - 5$

Change sides

$- \left(r\right) - 5 = - 21$

Add $5$ to both sides

$- \left(r\right) - 5 + 5 = - 21 + 5$

At this point we simplify both sides:

$- \left(r\right) = - 16$

And from here, we multiply both sides by $\left(- 1\right)$ to get our final answer in terms of positive $r$.

$r = 16$