Question

(5+root5) (5-root5) how to solve rational or not

Answer 1

(5 + root5 ) ( 5- root 5)
a^2 - b^2 = ( a + b ) (a- b)
5^2 - ( root 5)^2
= 25 - 5
=20
it is rational no.

Answer 2

$(5 - \sqrt{5} )(5 + \sqrt{5} )$
(a-b)(a+b)= a^2-b^2
$(5 - \sqrt{5} )(5 + \sqrt{5} ) = {5}^{2} - { \sqrt{5} }^{2}$
but 5^2= 25 and root 5^2 = 5.

$(5 - \sqrt{5} ) (5 + \sqrt{5} ) = 25 - 5$
= 20.

20is answer.

$<marquee><b><i>hope it helps u$.


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❤

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I'm sure please mark it as brainlist.