Determine if each function is even, odd or neither. Show all work and include an explanation of any symmetry that exists.
A) y = x^4 + 4x^2
B) y = 3x^3 - x - 3
C) y = x^5 - x^3 + x
D)y = 3
A) y = x^4 + 4x^2
B) y = 3x^3 - x - 3
C) y = x^5 - x^3 + x
D)y = 3