Can someone help me with this?

Question

You have 2 tests with scores of 83 and 92, assuming you can't get a score over 100 on any test. Determine all possible scores you can get to score an average of 90 on all 3 tests. Represent the answer algebraically.

Answer 1

if you mean exactly 90, then

83+92+x = 3*90

If you mean at least 90, then all scores from x to 100 will work.