posted by Watermelon .
The consecutive terms of an arithmetic progression are 5-x, 8, 2x. Find the common difference of the progression.
The common difference of an A.P. is constant, therefore, we can take the difference of consecutive terms and equate the values to determine x:
2x-8 = 8 - (5-x) =>
2x - x = 8-5+8 =>
x = 11