To solve for \( k \) in the equation \( f = \frac{g-h+k}{6} \), we need to isolate \( k \). This can be done by multiplying both sides of the equation by 6 to eliminate the fraction, and then rearranging the equation to solve for \( k \).
Step 1: Given Equation
We start with the equation:
\[
f = \frac{g - h + k}{6}
\]
Step 2: Multiply by 6
To eliminate the fraction, we multiply both sides by 6:
\[
6f = g - h + k
\]
Step 3: Rearranging the Equation
Next, we rearrange the equation to isolate \( k \):
\[
k = 6f + h - g
\]
Step 4: Substitute Values
Substituting the given values \( f = 7 \), \( g = 8 \), and \( h = 9 \):
\[
k = 6(7) + 9 - 8
\]
Step 5: Calculate \( k \)
Calculating the right-hand side:
\[
k = 42 + 9 - 8 = 43
\]
Final Answer
Thus, the value of \( k \) is:
\[
\boxed{k = 43}
\]