Answer
Thus, the first number is 5, and the second number is 7.
Work Step by Step
Using the hints provided, we create the two equations:
$3x-y= 8$
$x+y=12$
We substitute to find:
$3(12-y)-y=8$
This gives:
$36-4y=8$
$y = 7$
Since the sum of the numbers is 12:
$x = 12-7 = 5 $
Thus, the first number is 5, and the second number is 7.