Let, the numbers are: (a,b)
a + b = 14 -----(i)
a - b = 8 --------(ii)
a = 8 + b
Substitute for a in first equation:
8 + b + b = 14
8 + 2b = 14
2b = 14 - 8
2b = 6
b = 3
Now, substitute for b in first equation:
a + 3 = 14
a = 14 - 3
a = 11
In short, Final numbers would be (a,b) = (11,3)
Hope this helps!