Question

(-3 - 5i)(-3 + 5i) =

Answer 1

Hello,
You don't know (a-b)(a+b)=a²-b²?

(-3)²=9
(5i)²=-25
Answer 9 +25=34

Answer 2

(-3 - 5i)(-3 + 5i)
-3(-3 + 5i) - 5i(-3 + 5i)
-3(-3) - 3(5i) - 5i(-3) - 5i(5i)
9 - 15i + 15i - 25i²
9 - 25(-1)
9 + 25
34