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

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

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

Now, simplify the expression inside the parentheses:

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

So we have:

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

Now, multiply:

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

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