SOLUTION: Express the following in simplest form with a rational denominator. {{{(sqrt(2)-2) /(2sqrt(3)+sqrt(7))}}} So far I have: multipied it by {{{(sqrt(3) - 7) /(sqrt(3) - 7)}}} But

Algebra ->  Square-cubic-other-roots -> SOLUTION: Express the following in simplest form with a rational denominator. {{{(sqrt(2)-2) /(2sqrt(3)+sqrt(7))}}} So far I have: multipied it by {{{(sqrt(3) - 7) /(sqrt(3) - 7)}}} But      Log On


   



Question 187629: Express the following in simplest form with a rational denominator.
%28sqrt%282%29-2%29+%2F%282sqrt%283%29%2Bsqrt%287%29%29
So far I have: multipied it by %28sqrt%283%29+-+7%29+%2F%28sqrt%283%29+-+7%29
But after that I'm not to sure what to do. I don't even know if what I have done so far is right.

Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!

I think you left off the 2 coefficient and also you left
the square root symbol off of the 7 in what you 
multiplied by.

%28sqrt%282%29-2%29+%2F+%282sqrt%283%29%2Bsqrt%287%29%29

To find out what to multiply by,
take the denominator, 2sqrt%283%29%2Bsqrt%287%29
Change the sign of the SECOND term, so that
you have 2sqrt%283%29-sqrt%287%29  

Now put that over itself:%282sqrt%283%29-sqrt%287%29%29%2F%282sqrt%283%29-sqrt%287%29%29
so that it will just equal to 1 and therefore
it won't affect the value of the original 
problem when we multiply by it.

%28sqrt%282%29-2%29+%2F+%282sqrt%283%29%2Bsqrt%287%29%29%22%D7%22%282sqrt%283%29-sqrt%287%29%29+%2F+%282sqrt%283%29-sqrt%287%29%29

Put parentheses around all numerators and denominators:

%28%28sqrt%282%29-2%29%29+%2F+%28%282sqrt%283%29%2Bsqrt%287%29%29%29%22%D7%22%28%282sqrt%283%29-sqrt%287%29%29%29+%2F+%28%282sqrt%283%29-sqrt%287%29%29%29

Indicate the multiplication of the numerators and
denominators, so that we just have one fraction:



FOIL out the top and bottom:




The middle two tems in the bottom cancel out:



Take square roots of 9 and 49, which are 3 and 7:

+%28+2sqrt%286%29-sqrt%2814%29-4sqrt%283%29-2sqrt%287%29+%29%2F++%284%2A3-7%29+
+%28+2sqrt%286%29-sqrt%2814%29-4sqrt%283%29-2sqrt%287%29+%29%2F++%2812-7%29+
+%28+2sqrt%286%29-sqrt%2814%29-4sqrt%283%29-2sqrt%287%29+%29%2F5+

Edwin