What happens when you expand and factor (a + b + c)^3 - a^3 - b^3 - c^3?

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In summary: That's why I wanted to start by expanding (a + b + c)^3 and seeing if I could simplify the expression. In summary, to factor the expression (a + b + c)^3 - a^3 - b^3 - c^3, one can start by expanding (a + b + c)^3 and then applying the sum and difference of cubes to simplify the expression.
  • #1
mathdad
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Factor the expression.

(a + b + c)^3 - a^3 - b^3 - c^3

I believe the best way to tackle this problem is to expand (a + b + c)^3. By doing so, I should be able to cancel out -a^3 - b^3 - c^3, right?
 
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  • #2
RTCNTC said:
Factor the expression.

(a + b + c)^3 - a^3 - b^3 - c^3

I believe the best way to start problem is by expanding
(a + b + c)^3. By doing so, I should be able to cancel out
-a^3 - b^3 - c^3, right?
Start by writing it as $[(a+b+c)^3 - a^3] - [b^3 + c^3]$, and factor the contents of each of the square brackets as the difference (or sum) of two cubes.
 
  • #3
The difference of cubes is applied to
[(a + b + c)^3 - a^3] and the sum of cubes to [b^3 + c^3].

Correct?
 
  • #4
RTCNTC said:
The difference of cubes is applied to
[(a + b + c)^3 - a^3] and the sum of cubes to [b^3 + c^3].

Correct?
Yes! What happens when you do that?
 
  • #5
Opalg said:
Yes! What happens when you do that?

I have not completed the problem. So, my guess is that after applying the sum and difference of cubes, lots of terms will get canceled in the process.
 

1. What is factoring?

Factoring is a mathematical process where a polynomial is broken down into smaller, simpler parts. It involves finding the greatest common factor and then dividing the polynomial by that factor to get a simpler expression.

2. Why is factoring important?

Factoring is important because it allows us to solve equations and simplify expressions in a more efficient way. It also helps us to understand the relationships between different numbers and variables.

3. What are some common techniques used in factoring?

Some common techniques used in factoring include finding the greatest common factor, grouping terms, using the difference of squares formula, and using the quadratic formula.

4. How can factoring be applied in real life?

Factoring can be applied in real life situations such as in finance, where it is used to calculate interest rates and loan payments. It is also used in engineering to solve problems related to optimization and in physics to solve problems related to motion and acceleration.

5. What are some tips for factoring efficiently?

Some tips for factoring efficiently include practicing regularly, memorizing common factoring patterns, breaking down the polynomial into simpler parts, and making use of techniques like grouping and the difference of squares formula. It is also important to check your solutions and to keep practicing to improve your skills.

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