Question

Find the sum of the terms of the arithmetic sequence. 1, 7, 13, 19, . . ., 109 n = 19

A. 2204

B. 2090

C. 1045

D. 1102

Answer 1

can u find the common difference of your sequence >?

Answer 2

know what common difference is ?

Answer 3

nope lol

Answer 4

its the difference between current term and previous term.
so what is
13-7 = ?
7-1 = ?

Answer 5

13- 7 =6?
7-1=6?

Answer 6

yes! so common difference d= 6 . now what remains is just using the formula
\(\huge S_n=(n/2)(2a+(n-1)d)\)
where d= 6, n= 19 is given and a =1st term =1
can u calcilate sum now ?

Answer 7

im still confused

Answer 8

confused on what? substituting the values in formula ?