It is known that three numbers form an arithmetic sequence, the sum of which is equal to 15 and the sum of squares is equal to 107

It is known that three numbers form an arithmetic sequence, the sum of which is equal to 15 and the sum of squares is equal to 107

Since the three numbers are arithmetic sequence, the middle number is: 15 / 3 = 5
Let equal tea be X
(5-x)^2+5^2+(5+x)^2=107
25+X^2-10X+25+25+X^2-10X=107
2X^2=32
x^2=16
x=±4
When the equal difference is 4, the sequence is: (5-4), 5, (5 + 4), i.e. 1,5,9
When the difference is - 4, the sequence is: 5 - (- 4), 5,5 + (- 4), that is 9,5,1
Therefore, the arithmetic sequence is: 1,5,9