Answer:
r = -13
Step-by-step explanation:
Step 1: distribute the signs & terms outside the parenthesis. on the left side, distribute a - sign (same thing as -1) and on the right side distibute -7
12 - (3r) - (+2) = (-7)r + (-7)6
Step 2: algebraically simplify
10 - 3r = -7r - 42
52 = -4r
r = -13