I'm having trouble factoring

Hello, jenkinsbunch!

Factor: .\(\displaystyle 8x^3-1\)

I thought it would be \(\displaystyle (2x-1)^3\), but that didn't work.

Of course, it didn't work . . .

You're expected to recognize a difference of cubes:

. . . \(\displaystyle a^3 - b^3 \:=\:(a-b)(a^2+ab+b^2)\)


\(\displaystyle \text{You have: }\;(2x)^2 - 1^3\quad\hdots\quad\text{Got it?}\)

 
Hello,
I would like to add one piece of information if you dont' mind soroban.

The difference of cubes is:
a^3 - b^3 = (a-b)(a^2+ab+b^2) That means the when you have (b^3 = c = a perfect cube, such as -1, 1, 8, 64, etc) you can simply use that formula.

There is another formula though!

This one is:
a^3 + b^3 = (a + b)(a2 – ab + b2)
 
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