So, there's two equations we have here. We'll write them down
x + y = 69 (x will be the larger number)
x = 2y-3 (since it is three less than twice the smaller number, which is y)
So, when you look at the functions, we have a value for x. It would be 2y-3. So, we will plug in 2y-3 into x for the first equation. So, it'll turn to
(2y - 3) + y = 69
2y - 3 + y = 69
3y - 3 = 69
3y = 72
y=24
So, we have the value for the smaller number, 24. So, we will plug in 24 for y in the first equation. That means it will now become
x + (24) = 69
x = 45
So, the large number is 45, and the smaller number is 24