Why is (n-1)(n+1)=n^2-1?
Last Updated: 27.06.2025 01:56
xxx
xxx
xxx x
Mysterious fast radio bursts help astronomers pinpoint cosmic ‘missing’ matter - CNN
n^2 - 1
n^2 - n + n - 1
xx
xxx x
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
xxxx
xxxx
(n - 1)(n + 1)
And you are left with almost a square. One less than the square of side n.
The basic answer is that you cross-multiply the values in each factor:
The more direct answer is to look at a rectangle with sides of n + 1 and n - 1, let’s go with n = 2
Should you track your blood sugar with a continuous glucose monitor? - NPR
Move the nub up to the top: