Answer
$0.8$ must be added to both sides of the equation, not $-0.8$.
The correct solution is $r=13.4$.
Refer to the corrected work in the step-by-step part below.
Work Step by Step
To solve the equation $0.8$ must be added to both sides of the equation, not $-0.8$.
Thus, the correct solution is:
$\begin{align*}
-0.8+r&=12.6\\
r&=12.6+0.8\\
r&=13.4
\end{align*}$
