3r+6-r+2=3r-r+6+2=3+6+2=11

Move everything to the same side to make the equation equal zero

3r+6-r+2-3r+r-6-2-3-6-2-11=0

Collect like terms.

3r-r-3r+r+6+2-6-2-3-6-2-11=0

Solve

3r-r-3r+r=0

R=0, so just add the other numbers for the solution

6+2-6-2-3-6-2-11=-22