Why is (n-1)(n+1)=n^2-1?
11.06.2025 08:46

Move the nub up to the top:
xxx
xxx x
Could Patriots cut Stefon Diggs and owe him nothing? It’s complicated. - NBC Sports
xx
And you are left with almost a square. One less than the square of side n.
n^2 - n + n - 1
OpenAI claims to have hit $10B in annual revenue - TechCrunch
xxxx
xxx
xxx x
Angelina Jolie And Brad Pitt’s Daughter Shiloh Reintroduces Herself With New Name - HuffPost
So, that’s a rectangle with sides 2 and 4.
If you cut off the end of that rectangle, you make it smaller, 2 * 3 and a separate nub of size 1 * 2
n^2 - 1
Uber taps AI firm Wayve to pilot fully driverless rides in the UK - CNBC
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
The basic answer is that you cross-multiply the values in each factor:
Bruins Hire Former Forward Marco Sturm As New Head Coach - NESN
(n - 1)(n + 1)