The equation is

               (Add 5 to each side)

                      (Apply Additive inverse property: 5 – 5 = 0)

r = 13                             (Add:  5 + 8 = 13)

Check:

To check the solution, substitute r = 13 in original equation.

8=8                             (Subtract: 13 – 5= 8)

The statement is true.

          to graph the solution on the number line;

\
•        draw the number line
\
•       mark a dot at 13 on the number line
\

The value of r = 13.