Answer:
- 20 + 8i
Explanation:
Noting that i² = - 1
Given
[(6i + 9) + (4i - 5)] × 2i ← evaluate the terms inside the square bracket
= ( 6i + 9 + 4i - 5 ) × 2i
= (10i + 4) × 2i ← multiply each term in the parenthesis by 2i
= 20i² + 8i
= 20(- 1) + 8i
= - 20 + 8i