Answers

2016-07-04T21:58:01+08:00
Subtract x + y from 2x to get the common difference:
d = 2x - (x + y)
d = 2x - x - y
d = x - y

Using x - y as the common difference, the four means are:
4x - 2y, 5x - 3y, 6x - 4y, 7x - 5y
0