Answer
$\text{even}$
Work Step by Step
Recall:
a) A function is said to be odd, when every number $x$ in its domain, the number $-x$ is also in the domain such that $f(-x)=-f(x)$
b) A function is said to be even, when every number $x$ in its domain, the number $-x$ is also in the domain such that $f(-x)=f(x)$
Replace in the given function $x$ with $-x$ to evaluate $f(-x)$.
$f(-x)=2(-x)^4-(-x)^2 \\=2x^4-x^2 \\=f(x)$
Therefore, the function $f(x)$ is even.
