Question

If the 8" term of an ap is 37 and the 15 term is 15 more than the 12 term () find the first 3 terms of the ap (i) hence find the sum of first 15 terms of the ap

Answer 1

Step-by-step explanation:

a+7d = 37

a+4d - (a+11d) = 15

-5d = 15

d = -3

into the first:

a - 21 = 37

a = 58

sum(15) = (15/2)(116 + 14(-3))

= 555