# Using quadratic formula with a ^4

• November 21st 2012, 03:53 PM
minneola24
Using quadratic formula with a ^4
Hi,

I have this problem I need to find solutions for:

x^4-17x^2+77=0

I'm stuck on using the quadratic formula since its not in the right form im used to.

I ignored the ^4 and ^2 and did the formula but got something different than the book.

The book had the problem =x^2 not 0 anymore. Why is that?
• November 21st 2012, 04:21 PM
Plato
Re: Using quadratic formula with a ^4
Quote:

Originally Posted by minneola24
I have this problem I need to find solutions for:
$x^4-17x^2+77=0$

Can you solve $u^2-17u+77=0~?$

Then let $u=x^2~.$
• November 21st 2012, 04:26 PM
minneola24
Re: Using quadratic formula with a ^4
Thanks =) That helped