Question 29

Simplify: $$ \sqrt{( 7 + 3\sqrt{5} ) \times (7 - 3\sqrt{5})} $$

Solution

using identity ( a + b) ( a - b) = $$ a^2 - b^2 $$

$$ \sqrt{ 7^2 - (3\sqrt{5})^2 } $$

$$ \sqrt{49 - 45} $$

$$ \sqrt{4} = 2 $$

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