Find The Sum Of The First 8 Terms Of An Arithmetic Progression Whose First Term Is 5 And With A Common Difference Of 9.

find the sum of the first 8 terms of an arithmetic progression whose first term is 5 and with a common difference of 9.

 

Answer:

The sum is 292.

Step-by-step explanation:

Sum of arithmetic sequence/progression:

Sn = n/2 2(a₁) + (n-1)(d)

Where:

Sn = sum of the sequence  ⇒  Unknown

n = number of terms in a sequence  ⇒ 8

a₁ = the first term   ⇒ 5

d = the common difference  ⇒  9

Find the sum:

S₈ = (8/2) 2(5) + (8-1)(9)

S₈ = 4 10 + (7)(9)

S₈ = 4 10 + 63

S₈ = 4 (73)

S₈ = 292