Vermenigvuldigen en delen (a+bi)

Bereken

\((-6-9i) \cdot (-4+10i)\)

\((-6-9i) \cdot (-4+10i)= 24-60i +36 i-90i^2 = 24-60i +36 i+90= \color{red}{24+90}\color{blue}{-60i +36i}=\color{red}{114}\color{blue}{-24i}\)