This is the 12268th most frequent Russian word.
исполнившая
"Исполнившая" — "She who has performed or fulfilled."
Here, "исполнившая" serves as a participle form describing the subject "певица" (the singer) who completed the action of performing.
Певица, исполнившая эту песню, стала знаменитой.
The singer who performed this song became famous.
In this sentence, "исполнившая" relates to "задачу" (the task) and conveys a prior completion action attributed to the students.
Задачу, исполнившая ранее учеников, учитель проверил.
The task, previously completed by the students, was checked by the teacher.
"Исполнившая" is describing "актриса" (the actress) as having carried out the action of performing the role.