# Homework Help: HARDCORE Math lol!

1. Nov 30, 2004

### aisha

solve (4x^2-9)^2-11(4x^2-9)+24=0
I tried simplifying this and got 16x^4-44x^2+204=0 im not sure if this is right, and I dont know what to do to solve. Please help!

2. Nov 30, 2004

### Gokul43201

Staff Emeritus
Is there not a simple substitution that will make things easier ?

3. Nov 30, 2004

### aisha

There is nothing but the question, what do I do?

4. Nov 30, 2004

### Gokul43201

Staff Emeritus
Actually, I was making a suggestion there. Try a substitution...look for a repeating quantity and call it something.

5. Nov 30, 2004

### elote

let W = (4x^2-9), solve for W using some method, and then replace W with (4x^2-9), and now solve for x

:)

6. Nov 30, 2004

### aisha

Done needs to be checked plz!

Thanks I get how to do it but want to make sure I did it right can you please check? Here is what I did:
(4x^2-9)-11(4x^2-9)+24=0
Let w=(4x^2-9)
w^2-11w+24=0
factored to become (w-8)(w-3)=0
sub in w value (4x^2-9-8)(4x^2-9-3)=0
(4x^2-17) (4x^2-12)=0

so solving for x
4x^2-17=0
4x^2=17
x=the square root of +or- 17/4

or 4x^2-12=0
4x^2=12
x=the square root of +or-3

7. Nov 30, 2004

### Tom McCurdy

off the subject aisha, did you get your name from the ebaumsworld video aisha, I am sure it is on otherwebsites as well, but it is the video fo the skinny dude singing about some girl in want to be backstreet boys way?

8. Nov 30, 2004

### Gokul43201

Staff Emeritus
Correct...except that you mean x=+or- the square root of 17/4 NOT x=the square root of +or- 17/4

And Tom : 'Aisha' is a reasonably common name; originally of Persian origin, it has spread into other cultures as well.

9. Dec 1, 2004

### aisha

Thanks EVERYONE!!!