Question 281964
The three numbers would be x, x+2 and x+4.

3x is 3 times the first number
(x+2+x+4)-1 is one less than the sum of the second and third integers.

{{{3x = x+2+x+4-1}}}
{{{3x = 2x + 5}}}
{{{x = highlight (5)}}}

Answer:  5, 7, 9.

Proof:  5*3 = 15
7+9-1 = 15