The Cheater (1993)

Carter Phillips is under a lot of pressure to ace her math achievement exam - so much pressure that she gets Adam Messner to take the test for her . . . in exchange for one date. But Adam wants more than a date - much more. Carter has no choice. She has to do whatever he asks. If not, he'll tell her secret and ruin her life. Adam's control over her gets more and more unbearable. Carter is desperate to get rid of him - but how? Is murder the only way?