Step-by-step explanation:
19, 16, 13, 10, ...
a1 = 19
d = 16-19 = -3
the formula => an = a1 + (n-1)d
=> an = 19 + (n-1)(-3)
= 19 -3n +3
=> an = 22 - 3n or an = -3n +22
