Q15. Complex numbers

Explanation

(5 + 12i) - (9i² - 6i)

5 + 12i - 9i² + 6i

5 + 12i - 9(-1) + 6i

5 + 12i +9 + 6i

14 + 18i

Lesson

With addition / subtraction of complex numbers, you’re being tested on whether you can match like terms.

In addition, you need to know the values of i

√ - 1  = i

-1 = i²

- √ - 1  = i³

1= i⁴