Question

The sum of a certain number of terms of an AP series -8,-6,-4,..... is 52 the number of the terms is​

Answer 1

Answer:

52 = n/2[2×(-8)+(n-1)(2)]

104 = n[(-16)+2n-2]

104 = n[2n-18]

104 = 2n²-18n

52 = n²-9n

n²-9n-52 = 0

n²-13n+4n -52 = 0

n(n-13)+4(n-13) = 0

(n+4)(n-13) = 0

n = -4 (can't be)

n = 13 is the answer