Expert: Paul Klarreich - 2/7/2008

Question
I am working on 4 Algebra 1 problems and I cannot come to the correct answer, and don't know what I am overlooking to get the answer right. Please help. The problems deal with reducing fractions, either to multiply or dividing.

4. w^2 + 5w + 6
  ------------
  w^2 - w - 12

6. 3xyz^2 by  2y
  -----     ----
   6y^4     xz^4

7. r^2 + 7r + 10 by    3r - 30
  -------------    -------------
       3           r^2 - 5r - 50

18. simplifying the fraction
   4t^2 - 16
    -------
       8
     -----
     t - 2
     -----
       6  

Answer
Questioner:   Janine
Category:  Advanced Math
Private:  No
 
Subject:  Algebra 1
Question:  I am working on 4 Algebra 1 problems and I cannot come to the correct answer, and don't know what I am overlooking to get the answer right.

>> Well, I can' tell, either.  If I saw what you are doing wrong, I could tell you, but all you did was send the questions.  Does that mean that you just don't know how to get started?  

I will confine my response to that.


Please help. The problems deal with reducing fractions, either to multiply or dividing.
.......................................
4. w^2 + 5w + 6
 ------------
 w^2 - w - 12

Factor the top and bottom.  Then cancel any common factors.


6. 3xyz^2 by  2y
 -----     ----
  6y^4     xz^4


What is 'by'?  You didn't say what to do on this example, so I don't know whether these are to be multiplied or divided.

7. r^2 + 7r + 10 by    3r - 30
 -------------    -------------
      3           r^2 - 5r - 50

Same thing here.  

18. simplifying the fraction

  4t^2 - 16
   -------
      8
    -----
    t - 2
    -----
      6

This is a division of fractions.  Rewrite it as a multiplication:

  4t^2 - 16     6
  ---------  -------
      8      t - 2

Now factor all the numerators and denominators and cancel the common factors.

If you're still having trouble, send the examples again, WITH THE instructions for your 6 and 7, and the factoring work you did, and I'll try to help more.

You might need some practice in factoring. [Actually, that's what these examples are supposed to do.]