How Do You Factor a Cubic Equation Like a³c - a³b + b³a - b³c + c³b - c³a?

In summary, the conversation discusses how to factor a cubic equation with three variables. The Attempt at a Solution used grouping but was not successful. The final solution is given as (a+b+c)(b-c)(c-a)(a-b).
  • #1
bizkut
2
0
Factorising cubic equation

Anyone here know how to factor this equation?

Homework Statement



[tex]a^{3}c-a^{3}b+b^{3}a-b^{3}c+c^{3}b-c^{3}a[/tex]

The Attempt at a Solution



I tried factoring by grouping but ended up getting nowhere.

If anyone can factor this equation, please tell me step by step how you got it.
 
Last edited:
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  • #2
Cubics are bad enough but this has 3 variables. This is not a complete factorization but I think the most simplified form is
[tex](a^3c- ac^3)+ (b^3a- a^3b)+ (c^3b- b^3c)= ac(a^2- c^2)+ ab(b^2- a^2)+ bc(c^2- b^2)[/tex]
[tex]= ac(a- c)(a+ c)+ ab(b- a)(b+ a)+ bd(c- b)(c+ b)[/tex]
 
  • #3
thanks, that will be ok.

but if you could figure how to get this form, please let me know.
[tex](a+b+c)(b-c)(c-a)(a-b)[/tex]
 
  • #4
Notice the symmetry in the variables. Then, without loss of generality, treat it as a polynomial in a, and collect coefficients.
 
  • #5
Yeah, I'd have to agree with Gib Z
 

What is a cubic equation?

A cubic equation is a polynomial equation of the form ax^3 + bx^2 + cx + d = 0, where a, b, c, and d are constants and x is the variable. It is called a cubic equation because it has a highest degree of 3.

What is factoring?

Factoring is the process of finding two or more expressions that, when multiplied together, give the original expression. In the case of a cubic equation, factoring involves finding three linear or quadratic expressions that can be multiplied together to give the original cubic equation.

Why do we need to factor cubic equations?

Factoring cubic equations allows us to find the roots or solutions of the equation. This is important in many applications of mathematics, such as solving real-world problems and graphing functions.

What are the methods for factoring cubic equations?

The methods for factoring cubic equations include grouping, the rational roots theorem, and the cubic formula. These methods can also be combined to factor more complex cubic equations.

How do I know if I have factored a cubic equation correctly?

If you have factored a cubic equation correctly, the factors should multiply together to give the original equation and all the factors should be in the simplest form (no common factors). Additionally, the solutions to the equation should be the same as the roots of the factors.

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