Thread: A^3 / (A -2) = B Could someone solve this for 'A' ?

If B= A^3 / (A -2) what does 'A' equal?

Do you want an expression like: $\displaystyle A=...$ so in function of B?

Yes, I would like the equation solved in terms of A.
For example, if 2A^2 = B, then A = square root (B/2)

My first impression says it's not possible.

Originally Posted by wolf

Yes, I would like the equation solved in terms of A.
For example, if 2A^2 = B, then A = square root (B/2)

There are some conditions under which a cubic can be solved.
Here is a discussion.

Possible, but not fun, according to my cheating. It depends on why you'd need it.

Originally Posted by Quacky

Possible, but not fun, according to my cheating. It depends on why you'd need it.

That's indeed not really fun to do .

Thank you Siron, Plato and especially Quacky for the link to the answer.
At first that seems as if it's an easy equation to solve but not after looking at that answer.
Thanks everyone.

Yes polynomials do tend to "look" easy to solve because they have nice round integers as coefficients... but in general solving a polynomial algebraically is not easy. For instance solving $\displaystyle x^5 - 1 = 0$ is easy, make that $\displaystyle x^5 + 2x - 1 = 0$ and we're all stumped. In fact in practice polynomials are solved by approximation in the real world. But that doesn't mean it's wrong to learn how to solve cubics!