Step-by-step explanation:
[tex] - 2i(3 - 9i) \\ \\ = - 2i \times 3 + 2i \times \: 9i \\ \\ = - 6i + 18 {i}^{2} \\ \\ = - 6i + 18( - 1) \\ \\ = - 6i - 18 \\ \\ = - 18 - 6i \\ \\ = - (18 + 6i) \implies \: a + bi[/tex]
