Final answer:
To ensure continuity for the function at x = 3, the value of k must be 8 so that the function values from both piecewise segments match at that point.
Step-by-step explanation:
To find the value of k that makes the function f(x) continuous on any interval, we need to ensure the function values match at the point where the function definition changes, which is at x = 3. For the given function, f(x) = kx when 0 ≤ x < 3 and f(x) = 8x² when x ≥ 3, continuity at x = 3 means that k × 3 = 8 × 3². Solving this equation yields k = 8. Therefore, to ensure continuity at the point where x = 3, k must equal 8.