Find the sum of first thirteen terms of a linear sequence whose 8th term is 18 and 11th term is 24.

Answer 1

Please solve it for me

Answer 2

Just use your formulas
"8th term is 18" ---> a + 7d = 18
"11th term is 24 ---> a + 10d = 24
subtract them:
3d = 6
d = 2
in a+7d = 18 ---> a + 14 = 18 , a = 4

now use your sum(n) formula
your
a = 4
d = 2
n = 13

Answer 3

Find the sum of the first 13th term of a A P whose 8th term is 18 and 11th term is 24

Answer 4

What is a computer