#### Answer

The solution is 5

#### Work Step by Step

3r+4=19 Subtract 4 from both sides
3r+4 -4=19 -4 Simplify
3r =15 Divide by 3 on both sides
$\frac{3r}{3}$ =$\frac{15}{3}$
r=5
The solution is 5
Check
3r+4=19
3$\times$5 +4=19
15+4=19
19=19