I’m tired I’ve so much homework to complete and a long day of school :(
Just substitute the value of x from second equation into first equation:
N = x + y - n = 5
N = u + v + y - n = 5
N = 0 + y - n = 5
In short, N would be equal to y - n which is still equal to 5
Hope this helps!
The gcf of 25 and 60 is 5