### Step-by-Step Solution:
### Step 1: Rewrite the parabola equation in standard form
y^2 = kx - 8
### Step 2: Identify vertex form and properties of the parabola
p = \frac{k}{4}
### Step 3: Determine the vertex
\left(\frac{8}{k}, 0\right)
### Step 4: Location of the directrix
The directrix is at:
x = \frac{8}{k} - \frac{k}{4}
Given the directrix is \( x = 1 \):
\frac{8}{k} - \frac{k}{4} = 1
Simplify and solve the equation:
8 - \frac{k^2}{4} = k
\frac{k^2}{4} + k - 8 = 0
k^2 + 4k - 32 = 0
### Step 5: Solve the quadratic equation
Use the quadratic formula \( k = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \):
k = \frac{-4 \pm \sqrt{144}}{2}
k = \frac{-4 \pm 12}{2}
Thus, the solutions are:
k = \frac{-4 + 12}{2} = 4
k = \frac{-4 - 12}{2} = -8
Verify which value matches the directrix condition:
- For \( k = 4 \):
\frac{8}{4} - \frac{4}{4} = 2 - 1 = 1
This matches.
- For \( k = -8 \):
\frac{8}{-8} - \frac{-8}{4} = -1 + 2 = 1
This also matches.
Therefore, \( k = 4 \) satisfies the condition.
\boxed{k = 4}