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

1 answer

The student made an error when multiplying the imaginary units. The correct way to simplify the expression is as follows:

(−3i)(−5i)
= (-3)(-5)(i)(i)
= 15i²
Since i² is equal to -1, we can simplify further:

= 15(-1)
= -15

Therefore, the correct simplified expression is -15.