Question 301198
Okay I have two questions (5 +2 rad 3) squared. 
{{{(5 + 2sqrt(3))^2}}}
Multiply it same as any binomial squared:
= {{{25 + 20sqrt(3) + 4*3}}}
= {{{37 + 20sqrt(3)}}}
-----------------------
And another question is 5 over 2- rad 5
{{{5/(2 - sqrt(5))}}}
You didn't say, but usually the object is to get the radicals out of the denominator.
Multiply NUM and DEN by the conjugate of the DEN (2 + sqrt(5))
= {{{5(2+sqrt(5))/((2 - sqrt(5))*(2 + sqrt(5)))}}}
= {{{(10+5sqrt(5))/(4 - 5)}}}
= {{{-10 - 5sqrt(5)}}}