College Algebra, Chapter 1, 1.4, Section 1.4, Problem 26

Evaluate the expression $(5 - 3i)(1 + i)$ in the form of $a + bi$.


$\begin{equation} \begin{aligned} &= (5 - 3i)(1 + i) && \text{Using FOIL method}\\ \\ &= 5 + 5i - 3i - 3i^2 && \text{recall that } i^2 = -1\\ \\ &= 5 + 5i - 3i -3 (-1) && \text{combine like terms}\\ \\ &= 8+2i \end{aligned} \end{equation}$