Three numbers are known to form an arithmetic sequence. Their sum is 18 and their sum of squares is 126. Find these three numbers
Let these three numbers be a, B and C respectively
There are
B-A=C-B (1)
A+B+C=18 (2)
A^2+B^2+C^2=126 (3)
The solution is a = 3, B = 6, C = 9
Or a = 9, B = 6, C = 3