Respuesta :

Answer = 8

Because:

c(c + 3) - c(c-4) = 9c - 16
c^2 + 3c - c^2 + 4c = 9c - 16
3c + 4c = 9c - 16
7c = 9c - 16
7c + 16 = 9c
16 = 2c
8 = c