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

Last Updated: 16.06.2025 20:12

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

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

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

Why can't we send flat Earthers to space and show them the shape of Earth?

(n - 1)(n + 1)

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

What if Supergirl was a baby and not a teenager when she left Krypton? Who do you think will find her? What do you think things would be like?

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

n^2 - n + n - 1

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If you cloned 12 Michael Jordan's and 12 LeBron James' and had Team Jordan vs. James, which team would win the most games?

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

Move the nub up to the top:

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What is better, 4 more years of Trump with the media trying to hurt him, or 8 years of DeSantis with the media licking booty, or 4 to 8 years of RFK with the media hating on him all the time? (Biden is not an option, he can't win)

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What is the most inappropriate thing your wife has done in front of you?

n^2 - 1