Need help with a little algebra

[Istasi]

Hey guys,
I'm doing a math project involving revenue and cost for a company. Part of the project is algebraically determining the break-even point(s) of the venture. The two equations I must set equal are:

y=200+30x
y=x(95-2.5x)

Now, I know this would be 200+30x=x(95-2.5x) but after numerous attempts, I cannot seem to come up with a working answer. Please help!

(Note: I'm not necessarily asking you to solve this for me, just point me in the right direction)

[Stalking Shadow]

The equations are already set to y, so that makes it easy. You set them equal to each other, like you did, so:
200+30x=x(95-2.5x)

Then, distribute the x.
200+30x=95x-2.5x^2

Set the equation equal to 0, so you'll have a quadratic function
2.5x^2-65x+200=0

Use the quadratic formula
x=(-b (+/-) (b^2-4ac)^(1/2)))/2a
x=(65 (+/-) (65^2-4*2.5*200)^(1/2))/2*200
x=(65 (+/-) (4225-2000)^(1/2))/400
x=(65 (+/-) (2225)^(1/2))/400
x=(65 (+/-) 5(89^(1/2))/400

Simplify that last line, and it should be your answer, I think.
I 'unno. I'm not a math person.

[Alumette]

<runs in terror from the thread> :yoy:

[Istasi]

Thanks for the help Shadow. Turns out I had just made a stupid mistake, at the end of the quadratic formula I divided by 5 instead of negative 5. All I had to do was try to explain it to my mom who was trying to help to figure that out. D'oh!

[Kinetix]

<runs in terror from the thread> :yoy:
same

[Tsarmina]

*reads. is boggled. goes crosseyed. runs from thread screaming.* :notme:

[WingedAvenger]

It's conversations like these that make me glad I burned down my school.

[Solario]

It's conversations like this, that makes me very happy to have finally finished all my math, chemistry, science and physics this year. No more algebra, sin, cos etc. Now only sweet blissful stupidity.

On the downside, I haven't been away from it enough, because I still understood that.

[Istasi]

I'm glad to see I still have a few cards up my sleeve to make the masses filled with terror :chuckle:

[Quakester]

I'm glad to see I still have a few cards up my sleeve to make the masses filled with terror :chuckle:

It's things like this that make me really like Istasi. :chuckle:

Good job, kiddo. :D

[Noble]

heh, given enough time I would have gone a completely different way to solve that. Whenver I didn't understand something in pre-calculus I just found my own way to the answer, and often confused the hell out of the teacher on the way.