Why is (n-1)(n+1)=n^2-1?
09.06.2025 16:00

Move the nub up to the top:
xxx x
xx
n^2 - n + n - 1
And you are left with almost a square. One less than the square of side n.
xxx
xxxx
The more direct answer is to look at a rectangle with sides of n + 1 and n - 1, let’s go with n = 2
If you cut off the end of that rectangle, you make it smaller, 2 * 3 and a separate nub of size 1 * 2
People Can Fly cancels 2 games including Square Enix project - Video Games Chronicle
So, that’s a rectangle with sides 2 and 4.
xxx x
xxxx
Little-known cells might be key to human brain’s massive memory - The Washington Post
n^2 - 1
The basic answer is that you cross-multiply the values in each factor:
(n - 1)(n + 1)
Do you like Melania Trump's new official 1st lady black & white power portrait?
xxx