i don’t understand how to do these and this assignment is due today :((

Answer:
Step-by-step explanation:
8 , 12 , 16 , 20 .......
First term = a = 8
Common difference = second term - first term = 12 - 8= 4
nth term = a + (n-1) * d
= 8 + (n -1) * 4
= 8 + 4n - 4
= 4n + 8 - 4
= 4n + 4