1. The first three terms of an arithmetic sequence are given by x, (2x-5), 8.6.

Determine the first term and the common difference.

I know that d = t2 - 1 = t3 - t2

So, (2x-5)-(x) = 8.6 - (2x-5)(Trying to solve for difference)

x - 5 = 3.6 - 2x

-5 = 3.6 - x

-5-3.6 = - x

x = 8.6

x = d

This is what I did and it was wrong... I'm not sure how to do this question. :/

The answer is t1 = 6.2 d = 1.2