Here is function A - OCR - GCSE Maths - Question 9 - 2019 - Paper 4

To solve for the value of k, we need to analyze the function A:

1. The first operation is to subtract 4 from the input k:

   $k - 4$

2. The next operation is to multiply the result by 3:

   $3(k - 4)$

3. According to the question, the output must also equal k:

   $3(k - 4) = k$

4. To find k, we can solve the equation:

   • Distribute the 3:

   $3k - 12 = k$

   • Rearranging gives:

   $3k - k = 12$

   • Thus, we have:

   $2k = 12$

5. Dividing both sides by 2 yields:

   $k = 6$

Therefore, the value of k is 6.