Write an equation for the nth term of the arithmetic sequence
2,4,6,8,...

Step-by-step explanation:
dn means the difference (meaning what do you add/subtract to get the next number)
T0 means the term before the first one you got.
Tn = dn + T0
Tn = 2n + 0
Therefore our equation will be
Tn = 2n
Or in your case
An= 2n