Why is (n-1)(n+1)=n^2-1?
11.06.2025 04:20

n^2 - 1
n^2 - n + n - 1
The basic answer is that you cross-multiply the values in each factor:
We finally may be able to rid the world of mosquitoes. But should we? - The Washington Post
The more direct answer is to look at a rectangle with sides of n + 1 and n - 1, let’s go with n = 2
xx
(n - 1)(n + 1)
xxx
xxx
Move the nub up to the top:
What was your wildest experience as a lesbian?
xxx x
If you cut off the end of that rectangle, you make it smaller, 2 * 3 and a separate nub of size 1 * 2
And you are left with almost a square. One less than the square of side n.
xxx x
So, that’s a rectangle with sides 2 and 4.
xxxx
TSA issues warning as they ban certain card at airport security that's owned by millions - UNILAD
xxxx