Why is (n-1)(n+1)=n^2-1?
09.06.2025 01:00

If you cut off the end of that rectangle, you make it smaller, 2 * 3 and a separate nub of size 1 * 2
xxxx
xxx x
Woman on trial for poison mushroom killings says she was trying to fix "bland" meal - CBS News
So, that’s a rectangle with sides 2 and 4.
(n - 1)(n + 1)
xx
Yuen: When cancer struck a second time, she found ‘euphoria’ - Star Tribune
And you are left with almost a square. One less than the square of side n.
Move the nub up to the top:
n^2 - 1
US valley fever cases may be 18 times higher than reported - CIDRAP
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
n^2 - n + n - 1
—— which songs do certain kuorans remind you of?
xxx
xxx
The basic answer is that you cross-multiply the values in each factor:
xxx x