Question

\(\left(\sqrt{5}+2\right)\left(\sqrt{5}-1\right)\)

Answer 1

\(\left(\sqrt{5}+2\right)\left(\sqrt{5}-1\right)\\ =5-\sqrt{5}+2\sqrt{5}-2\\ =3+\sqrt{5}\)

Answer 2

`= sqrt 5^2 + 2 sqrt 5 - sqrt 5 - 2`

`= 5 + sqrt 5 - 2`

`= 3 + sqrt 5`

Answer 3

\(=5-\sqrt{5}+2\sqrt{5}-2=3+\sqrt{5}\)

Answer 4