Complex Function Evaluation

Let the function $$f(x)$$ be defined as:

$$f(x) = x^3 - 6x^2 + 9x + 8$$

Additionally, let another function $$g(x)$$ be defined as:

$$g(x) = 2f(x) - f(x - 1)$$

Determine the value of $$g(3)$$.