Jake and mike took a different number of tests. jake scored 85 points on each test. mike's total score was 15 less than jake's total score. the following expression shows mike's total score: 85x − 15 in the expression, what does the variable x represent? (5 points) select one: a. the total number of tests mike took b. the total number of tests jake took c. the sum of jake's and mike's total score d. the difference between jake's and mike's total score