Answer:
f(x) = |x|
Step-by-step explanation:
A function f(x) is called even function,
If f(-x) = f(x),
In first option
[tex]f(x)=|x|[/tex]
Since, f(-x) = |-x| = |x| = f(x)
⇒ f(x) is an even function,
In second option,
[tex]f(x)=x^3-1[/tex]
[tex]f(-x)=(-x)^3-1 = -x^3 - 1\neq f(x)[/tex]
⇒ f(x) is not an even function,
In third option,
[tex]f(x)=-3x[/tex]
[tex]f(-x)=-3(-x)=3x\neq f(x)[/tex]
⇒ f(x) is not an even function.
