Answer
First term(i = 1) $a_{1}$= (5$\times$1 + 3) = 5 + 3 = 8
Second term(i = 2)$a_{2}$ = (5$\times$2 + 3) = 10 + 3 = 13
Third term(i = 3)$a_{3}$ = (5$\times$3 + 3) = 15 + 3 = 18
Last term (i = 17) $a_{l}$ = (5$\times$17 + 3) = 85 + 3 = 88
The sequence becomes = 8 + 13 + 18 +......+ 88
Indicated Sum = 8 + 13 + 18 +......+ 88 = 816
Work Step by Step
First term(i = 1) $a_{1}$= (5$\times$1 + 3) = 5 + 3 = 8
Second term(i = 2)$a_{2}$ = (5$\times$2 + 3) = 10 + 3 = 13
Third term(i = 3)$a_{3}$ = (5$\times$3 + 3) = 15 + 3 = 18
Last term (i = 17) $a_{l}$ = (5$\times$17 + 3) = 85 + 3 = 88
The sequence becomes = 8 + 13 + 18 +......+ 88
Common difference (d)= 5
Number of terms (n) = 17
Indicated Sum = 8 + 13 + 18 +......+ 88
= $\frac{n}{2}$(first term + last term)
= $\frac{17}{2}$(8 + 88)
= $\frac{n}{2}$(96)
= 17 $\times$ 48
= 816