### Home > CCA2 > Chapter 9 > Lesson 9.2.1 > Problem9-57

9-57.

If $a = 2 + 3i$ and $b = 1 - i$, compute each of the following operations:

1. $a + b$

$(2 + 3i) + (1 - i)$
Combine like terms.

1. $a - b$

$1 + 4i$
Did you remember to distribute the negative?

1. $ab$

A generic rectangle can be used to multiply.
Remember that $i2 = -1$.

1. $\frac { a } { b }$

Multiply both the numerator and denominator by the complex conjugate of the denominator.

$-\frac{1}{2}+\frac{5}{2}i$