Answer:Jay needs a 94 on his next test to get an average of 93 on all of his exams.Step-by-step explanation:The way test averages work is you take the sum of all of your tests and divide it by the number of tests. So he got an 87 on test 1, a 98 on test 2, and an unknown score on test 3 because he hasn't taken it yet. Let x = that unknown score. The number of tests is 3. So we set up our equation as:(87 + 98 + x) / 3He wants an average of 93 so we set the equation equal to just that. (87 + 98 + x) / 3 = 93In order to isolate the numerator equation by itself, we multiply both side by 3. That way the 3 in the denominator on the left side cancels out. You now have:87 + 98 + x = 93(3)Simplify:185 + x = 279Now to get x by itself, we subtract 185 from both sides:x = 279 - 185x = 94He needs a score of 94 on the next test for the test average that he wants.