PLEASEEEE HELP IM SO LOST. i was sick and missed all the notes so i have no clue how to do this and now i have an F

Answer:
1- 25
2- im sorry its a hard one lol
3-confusion
Step-by-step explanation:
they count by odd numbers but skips on so instead of 1 3 5 its 1 5
Answer:
1.
A) common difference is 4
B) [tex]a_{7}[/tex]= 4+ (7-1)4
C) 28
Step-by-step explanation: