Answer:
The score on the next test must be between 86 and 98, inclusive
Explanation:
Write an inequality using the average:
86 ≤
≤ 90
Solve for x:
multiply everything by 3:
258 ≤ x + 83 + 89 ≤ 270
258 ≤ x + 172 ≤ 270
subtract 172 from everything:
86 ≤ x ≤ 98
The score on the next test must be between 86 and 98, inclusive