Question

( 5 + √ 5) * (5 - √ 5 )​

Answer 1

Answer:

$5 + \sqrt{5} \times 5 - \sqrt{5} \\ = {5}^{2} - { \sqrt{5} }^{2} \\ = 25 - 5 \\ = 20$

Answer 2

Answer:

(5+√5)*(5-√5)=5^2 - (√5)^2

=25-5=20

by a^2-b.^2=(a+b)*(a-b)

Hope this will help you