English subtitles

← Subtract Polynomials

Get Embed Code
1 Language

Showing Revision 1 created 02/22/2013 by Cogi-Admin.

  1. Now that you have a handle on adding polynomials, let's try subtracting them.
  2. When we subtract polynomials we need to subtract the second quanity. We can
  3. think of this problem just like this problem. We know in this problem we don't
  4. just subtract the 1. We need to subtract a total of 6. So we can subtract the 1,
  5. subtract the 2, and subtract the 3. This is why these parentheses are so
  6. important, they indicate that we need to subtract a total of 6 and not just a
  7. total of 1. We get an answer of 9 here but this isn't so important, what's
  8. important is what we did right here, distributed a negative 1. We're going to
  9. use this same line of thinking for tackling this. Whenever you subtract a
  10. quantity, you want to change every single sign. Because we're multiplying by a
  11. negative 1. So, I multiply each term by negative 1. And really that just changes
  12. all their signs. You don't have to show this step in your problem solving, but
  13. if it helps you do it. Here's our expression after we multiply by negative 1.
  14. Once we're here, we carry out the problem just like addition, we regroup our
  15. like terms and then we combine them. 5x squared, plus 2x, plus 2. Here's our
  16. final polynomial.