## Elementary Algebra

$-34+31i$
We first use the FOIL method to simplify the expression. Then, knowing that $i=\sqrt{-1}$, we can substitute $-1$ for $i^{2}$ to obtain: $(2+5i)(3+8i)$ =$2(3+8i)+5i(3+8i)$ =$6+16i+15i+40i^{2}$ =$6+31i+40i^{2}$ =$6+31i+40(-1)$ =$6-40+31i$ =$-34+31i$