Answer :
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!
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!