The 8th term of an ap is 17 and 19 term is 39 find the common difference

Question

asked Dec 8, 2021 207k views

1 Answer

David Woo · Answer 1 · 2021-12-12T08:33:43+0000

Answer:

2

Explanation:

an = a1 + d(n-1) is the formula

17 = a1 +d(8-1 ) = a1 *7d

39 = a1 +d (19-1) =a1+ 18d

We have 2 equations and 2 unknown. Subtract to eliminate a1

39 = a1 +18d

-17 = a1 +7d

--------------------

22 = 11d

Divide by 2

22/11 = 11d/11

2 =d

The common difference is 2