Help with a math problem(Solved)(Checked)

Golem

ok math wizards out there heres an example of the problems Im having trouble with.

2              x
__    =       __
 
x-1           10

basically Im trying to get it from that into

Ax^2 + Bx + C = 0

so that I can solve it. For some reason I have no problem solving problems through the quadratic method but cant seem to remeber how to simplify this properly. Obviously Im too stupid to see my mistake care to solve it? and then show the steps, or list a site explaining this method so I can review.

SeñorAmor

Cross multiply.

(x-1) * x = 2 * 10

or

x^2 - x = 20

or

x^2 - x - 20 = 0

FunkyWaltDogg

You have to get rid of that (x-1) in the denominator. Write yourself a note saying x =/= 1 (else you'd be dividing by zero in the initial setup), and then multiply both sides by 10(x-1) to clear both denominators. If you get x = 1 as one of your answers at the end, throw it away.

jclast

Golem wrote:

ok math wizards out there heres an example of the problems Im having trouble with.

2              x
__    =       __
 
x-1           10

basically Im trying to get it from that into

Ax^2 + Bx + C = 0

so that I can solve it. For some reason I have no problem solving problems through the quadratic method but cant seem to remeber how to simplify this properly. Obviously Im too stupid to see my mistake care to solve it? and then show the steps, or list a site explaining this method so I can review.

1.) Multiply both sides by 10. You get 20/(x-1) = x
2.) Multiply both sides by x-1. You get 20 = x^2 - x
3.) Set equal to 0. You get x^2 - x - 20 = 0.
4.) Quadratic away!

Golem

Thanks guys.

Incase your curious

x= -5
x= 4

(cant believe I was having such a hard time with such simple brain dead algebra)

Thanks for helping me out.

SeñorAmor

Golem wrote:

Thanks guys.

Incase your curious

x= -5
x= 4

(cant believe I was having such a hard time with such simple brain dead algebra)

Thanks for helping me out.

That can't be right.

2/(-6) != -5/10

also

2/3 != 4/10

Speleodot

You've got the minus signs the wrong way round, it's -4 or 5.

SeñorAmor

Speleodot wrote:

You've got the minus signs the wrong way round, it's -4 or 5.

Way to do ALL the work for him. :P

Golem

SeñorAmor wrote:

Golem wrote:

Thanks guys.

Incase your curious

x= -5
x= 4

(cant believe I was having such a hard time with such simple brain dead algebra)

Thanks for helping me out.

That can't be right.

2/(-6) != -5/10

also

2/3 != 4/10

If Im not mistaken:



right so if

x^2-x-20 =0

then

a = 1
b = -1
c = -20

plug them in and it comes out

x = -5
x = 4

am I right? (No because I copiedt the answer from my paper to the post wrong, BAH!!)

Golem

Speleodot wrote:

You've got the minus signs the wrong way round, it's -4 or 5.

oops your right I copied the answer wrong into my post.

Fucking negative signs.

Speleodot

It's easier to factorise it, but even if you do use the formula you get the minus signs the same way round as I said.

SeñorAmor

Remember, kids, equal fractions can be cross-multiplied. It's usually much easier than figuring out the common denominator.

Golem

Speleodot wrote:

It's easier to factorise it, but even if you do use the formula you get the minus signs the same way round as I said.

I made a program for my TI-83

Input A
Input B
Input C
[Negative Quadratic Formula] Sto -> M
[Positive Quadratic Formula ] Sto ->  N
Display M
Display N

I did them abunch by hand but since these quadratics equations are used alot in my drafting classes. So since Ive already passed math 2 or 3 years ago so I had to go back and remember how to do them. So ya when I was typing the answer I accidently switched the -'s.