Question

12 - 1 1\2 c = 2 1\2

Answer 1

12 - (1 1/2)C = 2 1/2.

12 - 3C/2 = 5/2,
-3C/2 = 5/2 - 12,
Multiply both sides by -2:
3C = -5 + 24,
3C = 19,
C = 19/3 = 6 1/3.