Which statement best describes how to determine whether [tex]f(x)=x^4-x^3[/tex] is an even function?
A. Determine whether [tex](-x)^4-(-x)^3[/tex] is equivalent to [tex]x^4-x^3[/tex].
B. Determine whether [tex](-x^4)-(-x^3)[/tex] is equivalent to [tex]x^4+x^3[/tex].
C. Determine whether [tex](-x)^4-(-x)^3[/tex] is equivalent to [tex]-(x^4-x^3)[/tex].
D. Determine whether [tex](-x^4)-(-x^3)[/tex] is equivalent to [tex]-(x^4+x^3)[/tex].