Chapter 4 - Polynomial and Rational Functions - 4.6 Complex Zeros; Fundamental Theorem of Algebra - 4.6 Assess Your Understanding - Page 240: 28

$1-3i,-1,6$

Step 1. Given a zero $x=1+3i$, we know another zero is $x=1-3i$, thus $(x-1-3i)(x-1+3i)=x^2-2x+10$ is a factor. Step 2. Perform a division as shown in the figure to get the quotient $x^2-5x-6$ (one can also perform synthetic divisions to get the same result). Step 3. Solve $x^2-5x-6=0$ or $(x+1)(x-6)=0$ to get $x=-1,6$