To find \((f - g)(x)\), we start with the functions:
\[ f(x) = -x^4 + 3x^2 - x + 1 \] \[ g(x) = \sqrt{-3x + 1} - 5 \]
Next, we need to compute \((f - g)(x)\):
\[ (f - g)(x) = f(x) - g(x) = f(x) - (\sqrt{-3x + 1} - 5) \]
This simplifies to:
\[ (f - g)(x) = f(x) + 5 - \sqrt{-3x + 1} \]
Substituting for \(f(x)\):
\[ (f - g)(x) = -x^4 + 3x^2 - x + 1 + 5 - \sqrt{-3x + 1} \] \[ = -x^4 + 3x^2 - x + 6 - \sqrt{-3x + 1} \]
So, we have:
\[ (f - g)(x) = -x^4 + 3x^2 - x + 6 - \sqrt{-3x + 1} \]
Now, let's determine the domain of \((f - g)(x)\). The domain is determined by the expression inside the square root of \(g(x)\), since the square root function requires that its argument be non-negative:
\[ -3x + 1 \geq 0 \]
Solving:
\[ -3x \geq -1 \] \[ x \leq \frac{1}{3} \]
Thus, the domain is
\[ (-\infty, \frac{1}{3}] \]
Putting this all together, the final answers are:
\[ (f - g)(x) = -x^4 + 3x^2 - x + 6 - \sqrt{-3x + 1} \] and the domain of \((f - g)(x)\) is
\[ (-\infty, \frac{1}{3}] \]