Chapter 3 - Polynomial and Rational Functions - 3.3 Zeros of Polynomial Functions - 3.3 Exercises - Page 338: 107

$\{\pm2i,\pm5i \}$

Step 1. Let $u=x^2$, we need to solve $u^2+29u+100=0$ or $(u+4)(u+25)=0$ which gives $u=-4,-25$ Step 2. For $u=-4$, we have $x^=-4$ and $x=\pm2i$ Step 3. For $u=-25$, we have $x^=-25$ and $x=\pm5i$ Step 4. The zeros are $\{\pm2i,\pm5i \}$