Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

Pages: **1**

**deiv****Guest**

Pls factor completely: (m^9)-(3m^3)-2

tnx....

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,426

hi deiv

Welcome to the forum.

You can simplify the problem by making the substitution

Then it becomes

I notice that x = -1 makes this expression zero, so by the factor theorem (x + 1) is a factor.

From there you can easily get the quadratic that goes with this and you'll find the formula will give another two factors.

Then you can go back to the m expression from there.

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 87,238

Hi;

Or take it over to Wolfram.

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

Offline

**deiv****Guest**

How about this one? What are the factors of:

3x(x+2y) + 4y(3x+2y)

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,426

What do you get if you multiply out the brackets and simplfy?

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 87,238

I think you are going to find that is irreducible in Q and therefore in Z.

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

Offline

Pages: **1**