Quandaries and Queries
  

 

My name is Emily Ann, and I am asking about an 11th grade problem. 2x/x2-9 - 6/x2+x-12

Thank you so much for your help
 

 

Hi Emily Ann,

This is very similar to evaluating

3 /4 - 1 /6

You need a common denominator.

4 = 2 2 and 6 = 2 3

so a common denominator is 2 2 3 = 12. Thus

3 /4 - 1 /6

= 3 /2 2 - 1 /2 3

= 3 3 /2 2 3 - 1 2 /2 2 3

= 9 /12 - 2 /12

= 7 /12

You have denominators of x2 - 9 and x2 + x - 12.

x2 - 9 = (x - 3)(x + 3) and x2 + x - 12 = (x - 3)( x + 4)

Thus a common denominator is (x - 3)(x + 3)(x + 4)

Can you complete the problem now?

Penny