According to the Remainder Theorem, when a polynomial \( f(x) \) is divided by \( x - c \), the remainder is equal to \( f(c) \).
In your case, you have \( f(x) = x^4 - 5x^3 + 8x \) and when it is divided by \( x - 3 \), the remainder is given as -30. According to the Remainder Theorem, this means:
\[ f(3) = -30 \]
So the correct response is:
f(3) = -30
f of 3 is equal to negative 30