Answer:
A). X = -18
Explanation:
-18 times 3 + 21 is -33. When you have a hard time figuing out these sort of problems, I suggest you should get each choice that is given. Put one of these choices one at a time in the equation and see if it will equal -33. To do this, you put the number and substiture it for x. This is an easy way of solving this problem especially when it is multiple choice.