# Thread: A bit of algebra

1. ## A bit of algebra

I'm working on a complicated geometery problem (see the Geometry forum) but I've hit an algebra brick wall. I need to rearrange the following in terms of a;

For clarity, a is the unknown. I know x, b and c

Can this be done? Any help appreciated

2. Originally Posted by xh558
I'm working on a complicated geometery problem (see the Geometry forum) but I've hit an algebra brick wall. I need to rearrange the following in terms of a;

For clarity, a is the unknown. I know x, b and c

Can this be done? Any help appreciated
Its a quartic in $a$ for which there is a formula (Google for it)

But are you sure that x is a variable rather than an operator?

RonL

3. ## Swoooosh!

I took a look at that quartic formula and experienced that swooooshing sound you hear when something flies right over the top of your head. I'll take another look later in the week (after the festivities) but I don't hold out much hope.

This is supposed to be a simple exercise in discovering the height of liquid in a half-empty cone frustum. I really don't think my lecturer intended it to be so difficult - which leads me to think there is a simpler solution just waiting to reveal itself.

http://www.mathhelpforum.com/math-he...l-frustum.html