Question

find first 3 terms of the arithmetic sequence with 5th term 26 and 7th term 68 ​

Answer 1

Answer:

Let a be the first term of the AP and d be the common difference

a+3d = 26;

a + 9d = 68

6d = 42 ; d = 7

Putting d = 7 ; a= 5

The AP is 5,12,19,26,33,40,47,54,61,68

The sum of first 10 terms can be found by ( n/2)(2a+(n-1)d) = 5(10 + (9)(7)) = 365

Step-by-step explanation: