The first three terms of an arithmetic progression are 2x, x+4 and 2x+7 respectively. Find the value of x.

I have no idea where to go from here – any help would be greatly appreciated, thanks in advance!

2 answers

recall that the terms of an AP have a common difference. That is,

(x+4)-2x = (2x+7)-(x+4)
Now just solve for x, and you're almost done.
Good