Answer
First term(i = 1) $a_{1}$= (-3$\times$1 + 5) = -3 + 5 = 2
Second term(i = 2)$a_{2}$ = (- 3$\times$2 + 5) = -6 + 5 = -1
Third term(i = 3)$a_{3}$ = (-3$\times$3 + 5) = -9 + 5 = -4
Last term $a_{l}$(i = 30) = $a_{30}$ = (-3$\times$30 + 5) = -90 + 5 = -85
The sequence becomes = 2 + (-1) + (-4) +......+ (-85)
Indicated Sum = 2 + (-1) + (-4) +......+ (-85) = -1245
Work Step by Step
First term(i = 1) $a_{1}$= (-3$\times$1 + 5) = -3 + 5 = 2
Second term(i = 2)$a_{2}$ = (- 3$\times$2 + 5) = -6 + 5 = -1
Third term(i = 3)$a_{3}$ = (-3$\times$3 + 5) = -9 + 5 = -4
Last term $a_{l}$(i = 30) = $a_{30}$ = (-3$\times$30 + 5) = -90 + 5 = -85
The sequence becomes = 2 + (-1) + (-4) +......+ (-85)
Common difference (d)= -4-(-1) = -1-2 = -3
Number of terms (n) = 30
Indicated Sum = 2 + (-1) + (-4) +......+ (-85)
= $\frac{n}{2}$(first term + last term)
= $\frac{30}{2}$(2 + (-85)
= $\frac{30}{2}$(-83)
= 15 $\times$ (-83)
= -1245