Algebraically determine whether the function j(x)=x^4-3x^2-4 is odd even or neither

We have the following definitions:
 A function is even if, for each x in the domain of f, f (- x) = f (x)
 A function is odd if, for each x in the domain of f, f (- x) = - f (x)
 Let's see the given function:
 j (x) = x ^ 4-3x ^ 2-4
 j (-x) = (- x) ^ 4-3 (-x) ^ 2-4
 Rewriting:
 j (-x) = (x) ^ 4-3 (x) ^ 2-4
 j (-x) = j (x)
 
 The function is even