Answer:
the answer you are looking for is -5<n<4
Let's start by moving all like terms to their own sides:
-18 = -3x + 6
3x = 6 + 18
3x = 24
x = 8
X + x + 1 + x + 2 + x + 3 = 330
4x + 6 = 330
4x = 324, x = 81
Smallest number: 81
Biggest number: 81 + 3 = 84
Sum: 81 + 84 = 165
The answer is 165