Question

simplify: (5+√5) (5-√5) ​

Answer 1

Given :-

Simplify :-

$ \sf{( 5 + \sqrt{5})(5 - \sqrt{5})}$

Solution :-

We can,

$ \sf{(5+ \sqrt{ 5 } )(5- \sqrt{ 5 } )}$

$ \to \sf{5^{2}-\left(\sqrt{5}\right)^{2} }$

$ \to \sf{25-\left(\sqrt{5}\right)^{2} }$

$ \to \sf{25-5 }$

$ ⇢ \sf{20 }$

Answer 2

$(5 + \sqrt5) (5 - \sqrt5)$

=5×5+5×√5-5×√5+√5×-√5

=25+5√5-5√5-5

=25-5=20