Barbara D. answered 09/12/23
PhD in Mathematics with 30+ Years of Teaching Experience
When you're working with more than two consecutive things (integers, odd numbers, whatever), sometimes it's easiest to let x be the middle one, instead of the first one.
Since we want three consecutive odd integers, we let the middle odd number be x.
The odd number just before x is: x - 2.
The odd number just after x is: x + 2.
We want the sum of these numbers to be 63, so
(x - 2) + x + (x + 2) = 63.
Simplify the left hand side and then divide both sides by 3:
3x = 63
x = 21
Notice that 21 is odd. That's good, because we're looking for odd numbers!
Since 21 is the second of the three consecutive odd numbers, all three numbers are 19, 21, and 23. (We're asked for all three integers, so we can't stop with just the value of x.)
It's a good idea to check our work: 19 + 21 + 23 does indeed equal 63.