Got a YouTube account?

New: enable viewer-created translations and captions on your YouTube channel!

English subtitles

← Divide Rational Expressions 6 - Visualizing Algebra

Get Embed Code
1 Language

Showing Revision 2 created 05/24/2016 by Udacity Robot.

  1. We start our problem by multiplying by the reciprocal of our second fraction. We
  2. flip it over. We can factor this first numerator as 5x plus 3 times 5x minus 3,
  3. since this is the difference of two perfect squares. Our denominator is also a
  4. difference of two perfect squares. So we have 2x plus 3 times 2x minus 3. For
  5. this fraction, we can factor this numerator by finding the factors of negative
  6. 18 that sum to negative 7. Those factors are negative 9 and positive 2. We use
  7. factoring by grouping to get 3x plus 1 times 2x minus 3 for this first
  8. numerator. And finally, for this denominator we find factors of positive 45 that
  9. sum to negative 14. Those two factors are negative 9 and negative 5. These
  10. factors let us rewrite our middle term, and then we can use factoring by
  11. grouping. We get a denominator of 5x minus 3 times 3x minus 1. Now that we have
  12. all of our factors, let's cancel factors that simplify to 1. These two factors
  13. would reduce to 1, and these two factors would also reduce to 1, leaving us with
  14. these factors for our answer. You're doing amazing at dividing rational
  15. expressions and factoring if you got this one correct.