Given `f(x)=-6(1-x)`, what is the value of `f(-8)`?

To find the value of \( f(-8) \), we can substitute \(-8\) into the function \( f(x) = -6(1 - x) \).

\[ f(-8) = -6(1 - (-8)) \]

Calculating the expression inside the parentheses:

\[ 1 - (-8) = 1 + 8 = 9 \]

Now substitute back into the function:

\[ f(-8) = -6(9) = -54 \]

Thus, the value of \( f(-8) \) is \(\boxed{-54}\).