### Home > INT2 > Chapter 8 > Lesson 8.1.1 > Problem8-19

8-19.

Multiply the following complex numbers. Write your answers in $a+bi$ form. Homework Help ✎

1. $(9i)(2i)$

Remember that $i^2 = -1$.

1. $(2 + i)(5 - i)$

$11 + 3i$

1. $(3 - i)(13i)$