Answer
Real zeros $\pm1, \pm2$
x-intercepts $\pm1, \pm2$.
Work Step by Step
Step 1. Real zeros $x^4-5x^2+4=0 \longrightarrow (x^2-1)(x^2-4)=0 \longrightarrow x=\pm1, \pm2$
Step 2. The x-intercepts are the same as the real zeros, that is $ x=\pm1, \pm2$.
