How do you simplify $(sqrt5-1)(sqrt5+3)$ ?

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Answer 1 · 2017-10-20T22:47:21

$2+2sqrt5$

Expand the brackets by using the FOIL method.

Multiply the First terms, the outside terms, the inside terms and the last terms.

$(sqrt5-1)(sqrt5+3)$
$=5+3sqrt5-sqrt5-3$
$=2+2sqrt5$

How do you simplify (sqrt5-1)(sqrt5+3)(sqrt5-1)(sqrt5+3)?