Answer:
x ≥ 83
Step-by-step explanation:
Scores for the first three tests are 79, 81, and 77
Let the score for the fourth test be x

Marianne must score an average of at least 80 points on 4 tests before she can apply for a scholarship
That is, average ≥ 80

Marianne score in her last test must be represented by x ≥ 83