A student has simplified the following expression incorrectly. Identify the mistake that was made and simplify the expression correctly. Show all necessary steps in the space provided. (−3i)(−5i) 15i

Answer 1

The mistake that was made is that the student incorrectly multiplied the terms -3i and -5i to get 15i.

To simplify the expression correctly, we will use the fact that i^2 = -1.

(-3i)(-5i) = -3 * -5 * i * i = 15 * i * i

Since i^2 = -1, this becomes:

15 * i * i = 15 * (-1) = -15

Therefore, the correct simplified expression is -15.