Why is (n-1)(n+1)=n^2-1?
Last Updated: 17.06.2025 02:15

xxxx
n^2 - n + n - 1
(n - 1)(n + 1)
xxx x
xxx
So, that’s a rectangle with sides 2 and 4.
Move the nub up to the top:
xxx
And you are left with almost a square. One less than the square of side n.
What is the best way to get over your ex?
If you cut off the end of that rectangle, you make it smaller, 2 * 3 and a separate nub of size 1 * 2
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 - 1
xx
The basic answer is that you cross-multiply the values in each factor:
xxxx
xxx x