SOLUTION: Okay I have two questions (5 +2 rad 3) squared. And another question is 5 over 2- rad 5. PLEASE help!!! I have a huge test tomorrow!!!!

Algebra ->  Radicals -> SOLUTION: Okay I have two questions (5 +2 rad 3) squared. And another question is 5 over 2- rad 5. PLEASE help!!! I have a huge test tomorrow!!!!      Log On


   



Question 301198: Okay I have two questions (5 +2 rad 3) squared. And another question is 5 over 2- rad 5. PLEASE help!!! I have a huge test tomorrow!!!!
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Okay I have two questions (5 +2 rad 3) squared.
%285+%2B+2sqrt%283%29%29%5E2
Multiply it same as any binomial squared:
= 25+%2B+20sqrt%283%29+%2B+4%2A3
= 37+%2B+20sqrt%283%29
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And another question is 5 over 2- rad 5
5%2F%282+-+sqrt%285%29%29
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%282%2Bsqrt%285%29%29%2F%28%282+-+sqrt%285%29%29%2A%282+%2B+sqrt%285%29%29%29
= %2810%2B5sqrt%285%29%29%2F%284+-+5%29
= -10+-+5sqrt%285%29