Question 37349
<pre><font size = 4><b>    25x 
—————-———— 
 10x + 15

Factor the numerator as 5·5·x

   5·5·x 
—————-———— 
 10x + 15 

Factor the denominator as 5(2x + 3)

   5·5·x 
——————-———— 
 5(2x + 3) 

Now you may divide out the 5's which I have colored red below

   <font color = "red">5</font>·5·x 
——————-———— 
 <font color = "red">5</font>(2x + 3)

Normally we just cancel them like this:
   1 
   <s>5</s>·5·x 
——————-———— 
 <s>5</s>(2x + 3)
 1

and get

    5·x 
——————-———— 
 (2x + 3)

The we write 5x for 5·x and erase the parentheses 
around the denominator:

   5x 
—————-——— 
 2x + 3

Edwin
AnlytcPhil@aol.com</pre>