Plz someone
write an explicit formula for the sequence{an} = {-3,-1/2,2,9/2,}. then find a17.
a) an= 5/2n-11/2; 37
b) an=3/2n-9/2; 21
c) an=5/2n-11/2; 69/2
d) an=-5/2n+11/2; -37

what is the 83rd term of the arithmetic system {an}={-22, -18,-}
a) -350
b)302
c)306
d) 354

write the series -25-22-19+ 14 terms using summation notation

after simplifying it i got: -36.25 as my answer. hope that !

step-by-step explanation: so we look at the formula un = a + (n-1)d

un is the amount of seats

n is the nth term aka row number

a is the original sequence/row number

d is the difference between each term

so in this a=22 d=6 and n can remain as n because we are simply formjng a rule

lets put these in the equation

un=22+(n-1)(6)

this is your answer to part a

however

lets double check that this is correct, we'll try putting it into the second term

un=a+(n-1)d

u2=22+(2-1)(6)

u2=22+6

u2=28

as the question said the second row has 28 seats so now we know the formula we made is correct.

as for part b

un=a+(n-1)

its asking us to find a row with 100 seats.

remember un was the amount of seata so all we do is substitute this in.

un=100 a=22 d=6

un=a+(n-1)d

100=22+(n-1)(6)

so now we simplify to find n which is the row number.

100-22=22+(n-1)(6)-22

78=(n-1)(6)

78/6=(n-1)(6)/6

13=n-1

13+1=n-1+1

14=n

so now we know that in the 14th row there is 100 seats.

hope this and that you understood! its my first time using the app or anyone out on here : p its also me to revise so a bunch! ask more questions if you dont understand ☺

the first sequence is an arithmetic sequence.