8, x, y, 4 <------> a, a+d, a+2d, a+3d
a+3d = 4, but we know a = 8
8 + 3d = 4
d = -4/3
x = a+d = 8-4/3 = 20/3
y = 20/3 - 4/3 = 16/3
check: next term would have to be 16/3 - 4/3 = 12/3 = 4, which it is.
If 8, x, y, +4 are an arithmetic progression, find x and y
1 answer