# Solving Rational equations

• Sep 25th 2011, 05:29 AM
Thenewguy
Solving Rational equations
http://www.tumblr.com/photo/1280/106...yqqzJUJ1qbctdd

Really need help with these 2 questions.
• Sep 25th 2011, 05:33 AM
Prove It
Re: Solving Rational equations
Quote:

Originally Posted by Thenewguy
http://www.tumblr.com/photo/1280/106...yqqzJUJ1qbctdd

Really need help with these 2 questions.

You need to remember that fractions can only be added or subtracted when they have a common denominator. Where is there a common denominator in Q.1? Or how could you make a common denominator? Same with Q.2, what is the common denominator?
• Sep 25th 2011, 05:38 AM
Thenewguy
Re: Solving Rational equations
yeah, i couldnt figure out the common denominator.. for these 2 questions
• Sep 25th 2011, 05:42 AM
Prove It
Re: Solving Rational equations
Quote:

Originally Posted by Thenewguy
yeah, i couldnt figure out the common denominator.. for these 2 questions

3x^2 - 24x + 48 = 3(x^2 - 8x + 16) = 3(x - 4)(x - 4) = (3x - 12)(x - 4)

What do you think you might have to multiply the numerator and denominator of the first term of question 1 by?
• Sep 25th 2011, 06:02 AM
Thenewguy
Re: Solving Rational equations
kay, so i have made the all of the denominator (3x-12)(x-4), the i have to multiplied (2x+2)(x-4),after adding and subtracting i got -2x^2-11x-19 = 0 , which i think is wrong, since it wouldnt work in the quadratic formula //first question answers are suppose to be 1 and -13.
• Sep 25th 2011, 06:12 AM
Prove It
Re: Solving Rational equations
Quote:

Originally Posted by Thenewguy
kay, so i have made the all of the denominator (3x-12)(x-4), the i have to multiplied (2x+2)(x-4),after adding and subtracting i got -2x^2-11x-19 = 0 , which i think is wrong, since it wouldnt work in the quadratic formula //first question answers are suppose to be 1 and -13.

I think you'll find that you should get

2x^2 - 6x - 8 - (4x^2 - 16) = 5x - 5

-2x^2 - 6x + 8 = 5x - 5

-2x^2 - 11x + 13 = 0
• Sep 25th 2011, 06:30 AM
Thenewguy
Re: Solving Rational equations
Thankks i got the answer. but what about for the second question. cause i only knew that k^2 +8k +12 = (k+2)(k+6) .. so the lcd cant possibly be (k-2)(k-6)(k+2)(k+6) lool...
• Sep 25th 2011, 06:32 AM
Prove It
Re: Solving Rational equations
Quote:

Originally Posted by Thenewguy
Thankks i got the answer. but what about for the second question. cause i only knew that k^2 +8k +12 = (k+2)(k+6) .. so the lcd cant possibly be (k-2)(k-6)(k+2)(k+6) lool...

Why do you think that the LCD isn't this? Because that's exactly what it is...