Question

In an arithmetic sequence, the 10th term is 37, and the 21st term is 4. Find the common difference and the first term

Answer 1

Common difference is 3. And the first term is 64.

Explanation:

The differnce between 21 and 10 is 11. So there are 11 unknown numbers in between. And the difference between 37 and 4 is 33. 33/11 is equal to 3. So the pattern is minus three. the first term is 9 terms before 37. 9 times 3 is 27. 37+27 is equal to 64. so the first term is 64