Question 523381
Three consecutive odd numbers could be defined as x, y, and z.  
But then you have 3 unkowns, so you need 3 equations to find a solution.
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However, you know the numbers are consecutive odd numbers.
So, the first can be defined as 'x'.
That means the next two odd numbers is 'x+2' and 'x+4'.
Now you have only one unknown: 'x'.
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And you know the sum of the three consecutive odd integers is 129.
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If you were to have defined x + y + z = 129, then you would be stopped in your tracks.
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But you've cleverly defined the numbers in terms of one unknown, 'x.'
So,
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x +(x+2) +(x+4) = 129
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3x +6 = 129
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3x = 123
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x = 41
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Great!  x is an odd integer!
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x+2 = 43
x+4 = 45
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Now we have three consecutive odd integers:  41, 43, and 45.
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But check to ensure they total 129.
41+43+45 = 3*40 + (1+3+5) = 120 + 9 = 129
Correct.
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Answer:  The three consecutive odd integers that sum 129 are:  41, 43, and 45.
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Done.