Stand and Deliver
(1995)

The entire A.P. calculus class is suspected of cheating since they all passed the exam and all made similar mistakes.  The class decides to retake the test, which is even more difficult, under the supervision of the Educational Testing Service.  They all pass again, and their teacher, Mr. Escalante (Edward James Olmos), asks for the original scores to be reinstated.

Thanks Drummer Brian!