let 'x' be the smaller number
let 'y' be the larger number
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"the sum of the two numbers is 124"
x + y = 124 -equation 1
"three times the smaller number exceeds the larger number by 12"
-equation 2
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from equation 2
3x = y + 12
y = 3x - 12 -equation 3
substitute equation 3 to equation 1
x + y = 124
x + (3x - 12) = 124
x + 3x - 12 = 124
4x = 124 + 12
4x = 136
x = 34
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substitute x to equation 3
y = 3x - 12
y = 3 (34) - 12
y = 90
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therefore the numbers are 34 & 90
