SOLUTION: How would I simplify the product to this problem? (√5 + 2)(√5 - 6)

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Question 309038: How would I simplify the product to this problem?
(√5 + 2)(√5 - 6)
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Let z=sqrt%285%29 to get the expression %28z%2B2%29%28z-6%29


%28z%2B2%29%28z-6%29 Start with the given expression.


z%5E2-6z%2B2z-12 FOIL


z%5E2-4z-12 Combine like terms.


%28sqrt%285%29%29%5E2-4%2Asqrt%285%29-12 Plug in z=sqrt%285%29


5-4%2Asqrt%285%29-12 Square sqrt%285%29 to get 5


-7-4%2Asqrt%285%29 Combine like terms.


So %28sqrt%285%29%2B2%29%28sqrt%285%29-6%29=-7-4%2Asqrt%285%29