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Precalculus 11 Online
OpenStudy (littlenugget):

HELP!!! FAN AND MEDAL!!!!!

OpenStudy (littlenugget):

\[\frac{ x-3 }{ x }+\frac{ 3 }{x ^{2} +x }=\frac{ 3 }{ x+1 }\] Solve.

OpenStudy (debbieg):

Factor the 2nd denominator. Now - what's the LCD? Multiply both sides of the equation by that, and *poof* all the fractions will disappear. Then you should have a quadratic equation to solve - either by factoring (if possible) or quadratic formula (if not). Be sure to check for extraneous solutions!

OpenStudy (littlenugget):

Is the LCD x?

OpenStudy (debbieg):

No - remember that the LCD has to be a MULTIPLE of ALL the denominators. And x+1 is not a multiple of x. Did you factor the 2nd denominator? What do you get? You HAVE to see all the factors before you can determine the LCD.

OpenStudy (littlenugget):

I got x(x+1)

OpenStudy (debbieg):

ok, good. So your denominators are: x x+1 x(x+1) So what's the LCD?

OpenStudy (littlenugget):

I'm not sure, x+1?

OpenStudy (debbieg):

No, because x is not a multiple of (x+1). The LCD has to be a multiple of the all the denominators, just like with numbers. I have to be able to take each denominator, and multiply it by SOMETHING (possibly 1) and GET the LCD. I need an LCD so that: x(?)=LCD (x+1)(?)=LCD x(x+1)(?)=LCD Remember, the (?) might be 1, but there has to be SOME PRODUCT with each denominator that gets me to the LCD.

OpenStudy (debbieg):

In other words, there is nothing I can put in for the "?" so that: x(?)=x+1 or (x+1)(?)=x So neither of those (alone) are the LCD.

OpenStudy (littlenugget):

so then i would have to multiply by x(x+1)?

OpenStudy (littlenugget):

So would i like multiply the first fraction by (x+1) and the last by x?

OpenStudy (littlenugget):

so they would all be x(x+1)?

OpenStudy (debbieg):

Right! Your LCD is x(x+1). Multiply both sides of the equation by that. In the first term, left side, x's cancel so you get (x-3)(x+1). In 2nd term, left side, the whole denominator cancels with LCD. On right side, x+1 cancels so you get 3x. Now take the FOIL product of the binomials, gather all terms on left side to set =0. You have a quadratic equation. Solve using quadratic equation methods.

OpenStudy (littlenugget):

So would my work be: (x-3)(x+1)+3=3x then x^2+x-3x-3+3=3x then x^2-2x=3x then x^2-5x=0?

OpenStudy (littlenugget):

@DebbieG

OpenStudy (littlenugget):

never mind i made silly mistake

OpenStudy (littlenugget):

:(

OpenStudy (littlenugget):

help.....

OpenStudy (littlenugget):

haha i got it, never mind :)

OpenStudy (debbieg):

Sorry, I missed the notifications above. Glad you got it! :)

OpenStudy (littlenugget):

thanks for being so patient with me :) sorry it took me a long time to understand xD

OpenStudy (littlenugget):

I understand it now :D

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