If -5c + 6 = 69, that would mean the value of c is -12.6 because:
-12.6 • (-5) = 63
63 + 6 = 69
Given the value of c is -12.6, we can substitute this into our next expression:
6(-12.6) = -75.6
-75.6 - 15 = -90.6
The value of 6c - 15 is equivalent to -90.6.