X/3 - 7 = $33.
X/3 = 33 + 7 [Add $7 to each side]
X/3 = 40
X = $120 [Multiply both sides by 3]
-4k + 12 = 60.
-4k = 48 [Subtract 12 from each side]
k = -12 [Divide each side by -4]
9/5 (45) + 32 = 9(45/5) + 32 = 9(9) + 32 = 81 + 32 = 113 degrees F.
I made the same mistake you did at first, adding 8+3 to get 10.