Answer :
Use the geometric series formula:
S_n = [a_1(1 - r^(n)]/(1 - r)
Let a_1 = 3
Let n = 8
Let r = 1/2
S_8 = [3(1 - (1/2)^8]/[(1 - (1/2)]
Simplify the right side using your calculator to find S_8, which is the sum of the first 8 terms.
Use the geometric series formula:
S_n = [a_1(1 - r^(n)]/(1 - r)
Let a_1 = 3
Let n = 8
Let r = 1/2
S_8 = [3(1 - (1/2)^8]/[(1 - (1/2)]
Simplify the right side using your calculator to find S_8, which is the sum of the first 8 terms.