Why is (n-1)(n+1)=n^2-1?
14.06.2025 08:14

(n - 1)(n + 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
xxx x
xxx x
And you are left with almost a square. One less than the square of side n.
So, that’s a rectangle with sides 2 and 4.
n^2 - 1
xxx
xxx
n^2 - n + n - 1
xx
xxxx
Do snipers lay on top of tank turrets during combat?
Move the nub up to the top:
xxxx
The basic answer is that you cross-multiply the values in each factor:
Why do you allow your cat to lie in bed with you?
If you cut off the end of that rectangle, you make it smaller, 2 * 3 and a separate nub of size 1 * 2