Question 105169
{{{(6-sqrt(20))/2}}}

we can write this as a difference of two radicals

{{{6/2 - sqrt(20)/2}}}

now, we can write number {{{20}}} as a product of {{{4}}} and {{{5}}}

{{{6/2 - sqrt(4*5)/2}}}

{{{3 - 2sqrt(5)/2}}}

and, finally, we will have

{{{3 - sqrt(5)}}}