Answer:
36
Explanation:
Since x = 4, the question is asking you to replace the "x" in the expression with "4". Once you have made this substitution, you can see the the "9" and "4" are directly next to each other. This means that they should be multiplied together. Therefore, when x = 4, the value of the expression is be 36.
9x ----> 9(4) ----> 36