SOLUTION: (2√5-3√2) / (2√5+3√2) ..rationalize the numerator i cant seem to do .. help will be appreciated !!

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Question 207713: (2√5-3√2) / (2√5+3√2) ..rationalize the numerator i cant seem to do .. help will be appreciated !!
Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
%282sqrt%285%29-3sqrt%282%29%29%2F%282sqrt%285%29%2B3sqrt%282%29%29

Put parentheses around it like this:

%28%282sqrt%285%29-3sqrt%282%29%29%2F%282sqrt%285%29%2B3sqrt%282%29%29%29


Form the conjugate of whichever you want to rationalize.
In this case the numerator.  The numerator is 2sqrt%285%29-3sqrt%282%29,
It's conjugate is gotten by changing the sign of the second term.
So its conjugate is 2sqrt%285%29%2B3sqrt%282%29.

Now you put that over itself, like this and put it in 
parentheses:

%28%282sqrt%285%29%2B3sqrt%282%29%29%2F%282sqrt%285%29%2B3sqrt%282%29%29%29

Now you multiply these together:



Now you FOIL out the tops and the bottoms:



The middle two terms on top cancel:



And the two terms add together on the bottom:

%284sqrt%2825%29-9sqrt%284%29%29%2F%284sqrt%2825%29%2B12sqrt%2810%29%2B9sqrt%284%29%29

Now we know the square roots of 25 and 4 so we get

%284%2A5-9%2A2%29%2F%284%2A5%2B12sqrt%2810%29%2B9%2A2%29

%2820-18%29%2F%2820%2B12sqrt%2810%29%2B18%29

2%2F%2838%2B12sqrt%2810%29%29

Factor 2 out of the bottom:

2%2F%282%2819%2B6sqrt%2810%29%29%29

Cancel the 2's:

cross%282%29%5E1%2F%28cross%282%29%5B1%5D%2819%2B6sqrt%2810%29%29%29

1%2F%2819%2B6sqrt%2810%29%29

Now the numerator is rational, because it doesn't
contain any square roots.

Edwin