Explicación paso a paso:
(√5 + 1)² - (2√5)² + 3
= [(√5 + 1) x (√5 + 1) - (2√5) x (2√5)] + 3
= [5 + 2√5 + 1 - 8√5 + 3]
= 5 - 6√5 + 3
= 3 - 2√5
