The absolute value is the distance from 0, so it would be 4 and -4
a. 14, 18, 22, 26.... It is +4
b. 2,430, 7,290, 21,870..... It is x3
c. So it is going -2, -4, -6, -8 so the next one would be -10 which is -13 then -12 which is -25 and so on.
Hope this helps!
16 people would be at the dinner because Jim and Sarah invited 7 friends and each friend brought 1 guest, so you do 7*2=14 and the 14 + Jim and Sarah=16 people.