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

13.06.2025 08:03

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

n^2 - n + n - 1

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

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What is the sum of X+XX+XXX+XXXX?

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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

What baseball stories from the early days of the sport seem too bizarre to be true?

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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

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

What is the most gay experience with your dad?

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(n - 1)(n + 1)

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Were the 1980s as uptight and prudish as movies and TV shows make them out to be? When I think of 80s culture, I think about a very "icky" judgmental yuppie status quo time period.

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

Is it possible to revive a dead person in real life with black magic?

Move the nub up to the top: