x ≥ 83
Explanation:Scores for the first three tests are 79, 81, and 77
Let the score for the fourth test be x
[tex]\begin{gathered} \text{Average = }\frac{79+81+77+x}{4} \\ \text{Average = }\frac{237+x}{4} \end{gathered}[/tex]Marianne must score an average of at least 80 points on 4 tests before she can apply for a scholarship
That is, average ≥ 80
[tex]\begin{gathered} \frac{237+x}{4}\ge80 \\ 237+x\ge4(80) \\ 237+x\ge320 \\ x\ge320-237 \\ x\ge83 \end{gathered}[/tex]Marianne score in her last test must be represented by x ≥ 83
