We haven n! = (n-1)! x n and (n+1)! = n! x (n + 1);
Then, (n!)^2 = n! x n! = n! x (n-1)! x n;
And (n+1)!(n-1)! = n! x (n + 1) x (n-1)!;
Finally, [n! x (n-1)! x n] / [n! x (n + 1) x (n-1)!] = (n+1)/n;
I think it is 640.. What they mean is every inch equals 4 feet so you would multiply 8*4 and 5*4 then you get 32 and 20.. im sure you know area but just incase its base times height so 32*20=640
The GCF is 5x because 5x goes into all the sets.
Please see the pic, I'd solved your question in it.
