Why is (n-1)(n+1)=n^2-1?

11.06.2025 01:03

Why is (n-1)(n+1)=n^2-1?

xxx

xxx

xxxx

Why are US customs agents so talkative? I cringed hard when a US customs agent asked me if I was on vacation. He doesn’t need to know why I went to another country as long as I am a U.S. citizen.

The basic answer is that you cross-multiply the values in each factor:

n^2 - n + n - 1

(n - 1)(n + 1)

Meghan Markle and Prince Harry take kids to Disneyland and the family photos are magical - HOLA

The more direct answer is to look at a rectangle with sides of n + 1 and n - 1, let’s go with n = 2

xxx x

xx

How do you explain the involvement of a mainland Chinese visitor, her local relative, and a 65-year-old friend of the latter in the suspected money laundering case seized by Hong Kong police?

So, that’s a rectangle with sides 2 and 4.

xxx x

xxxx

How does a 45-year-old man get a girlfriend?

n^2 - 1

Move the nub up to the top:

If you cut off the end of that rectangle, you make it smaller, 2 * 3 and a separate nub of size 1 * 2

What is the American mobile phone number format?

And you are left with almost a square. One less than the square of side n.