# Homework Help: Algebra: factor problem.

1. Aug 9, 2011

### Miike012

Is this term factorable?

9a^2 - 6a + 1 -x^2 - 8dx - 16d^2

I dont see anything that I can group or any simple factors to factor out...

2. Aug 9, 2011

### PeterO

Group the first 3 and the second 3 with careful management of - signs

3. Aug 9, 2011

### Miike012

9a^2 - 6a + 1 - (x^2 + 8dx + 16d^2)

= (3a - 1)^2 - (x + 4d)^2

= (3a - 1 + x + 4d)(3a - 1 - x - 4d)

How do you know what the roots are?

4. Aug 9, 2011

### PeterO

Not exactly sure what roots you are after? Expressions have factors - you have done that. Equations have roots - you don't have an equation???

EDIT: The following post spilled the beans about what I was trying to get you to think about.

Last edited: Aug 9, 2011
5. Aug 9, 2011

### Bohrok

If it were a function in x where a and d are unknown constants, you could set the factored expression equal to 0, solve for x, and express the roots in terms of a and d.

6. Aug 9, 2011

### Miike012

thank you for your guys help.

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