Help me ples

I tried my best and got no luck which is why I asked you guys for help

I have given you help and I have asked you to respond. (Which you have not done, complaining does not count)

Add up the middle row, what do you get?

why are you having difficulty with such a simple question. As Melody suggests:

Top row =(n+1) + 1 + (n - 1)=Diagonal from top left-hand corner=(n+1) + (2n-9) + 2

(n+1) + 1 + (n - 1)=(n+1) + (2n-9) + 2

2n + 1 =3n - 6

3n - 2n =6 + 1

n == 7

Do you mean the sum of the middle row?

3+2n-9+n

= +2n+n   +3-9

=     3n         -6

Now the top row was   2n + 1

and the middle row is   3n - 6

so

2n + 1 = 3n - 6

2n + 1 -2n= 3n - 6 -2n

           + 1 = 1n - 6

     + 1 +6 = 1n - 6 +6

           7   =  n

            n = 7