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← Working with Negatives - Visualizing Algebra

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Showing Revision 2 created 05/25/2016 by Udacity Robot.

  1. Okay, for this first one, I know a negative exponent really means a reciprocal.
  2. So I'm going to have 1/3 squared. Well that's 1/3 times 1/3, which is 1/9. I
  3. know 1/9 isn't equal to negative 9, so this one's out. Here I have the negative
  4. of 3 squared. Remember this is a negative 1 in front times 3 squared. Exponents
  5. come before a multiplication. So I have 3 squared, which is 9, and then have to
  6. multiply it by negative 1, so I get negative 9. That one's right. Here, negative
  7. 3 squared is just negative 3 times negative 3, or positive 9, so that one's out.
  8. Here, I have 1/3 squared. Well, I know 1/3 squared is 1/9 from before, so I know
  9. that one's out. Here, I need to do the reciprocal first. I'm going to flip one
  10. third over. The reciprocal of 1/3 is 3. So I have negative 1 times 3 squared.
  11. This negative 1 came from right here. Remember, there's a negative 1 in front of
  12. this parenthesis. I have negative 1 times this quantity squared. 3 squared is 9.
  13. So I have negative 1 times 9, or negative 9. This answer is correct. For this
  14. last one, I have negative 1/3 squared. I just write this quantity twice,
  15. negative 1/3 times negative 1/3, so I get positive 1/9. That's not equal to -9,
  16. so that's not my answer either. Only these two are correct. If you got that quiz
  17. right, great job. You really understand negatives and exponents. It's okay if
  18. you didn't get it right the first time, but hopefully you learned something
  19. along the way, and how to work with these negative numbers.