[tex]a^{2}[/tex] is just a*a, and [tex]a^{4}[/tex] is a*a*a*a
Thus, adding them together is a*a a*a*a*a, or [tex]a^{6}[/tex]
Alternatively, use the rule
[tex]a^{m} +a^{n} =a^{m+n}[/tex]
When used in this problem:
[tex]a^{2} +a^{4} =a^{2+4} = a^{6}[/tex]
I hope this helps!
