-3i (i + 5)

Question

answer choices:

-18i

-3i^2 -15i

3 - 15i

15

Answer 1

To simplify the expression \(-3i (i + 5)\), we can distribute \(-3i\) to both terms inside the parentheses:

\[ -3i \cdot i + (-3i) \cdot 5 = -3i^2 - 15i \]

Now, we can recall that \(i^2 = -1\). Thus, we substitute this into the expression:

\[ -3(-1) - 15i = 3 - 15i \]

So the simplified expression is:

\[ 3 - 15i \]

Therefore, the correct answer is:

3 - 15i