Which algebraic expression represents the difference of e squared and twenty-one? A. E2+21 b.21 times e2 c. E2 - 21 d. 21 divided by e2

Sanderson is having trouble with his assignment. his shown work is as follows: − 3 7 7 3 = − 3 7 × 7 3 = − 21 21 = −1 however, his answer does not match the answer that his teacher gives him. complete the description of sanderson's mistake. find the correct answer.