Answer:
a = -15, b = -.5, c = -1
Explanation:
1/3a = -5 --> multiply each side with 3 --> a = -15
12 - b = 12.5 --> subtract 12 from both sides --> -b = .5 --> multiply each side with -1 to get b positive --> b = -.5
.1 = -10c --> multiply each side with -10 --> c = -1