Question 57323
Hi ac, 
You're close.
{{{(18+sqrt(567))/9}}}
567=81*7, 81 is a perfect square, 9*9=81
{{{(18+sqrt(81)*sqrt(7))/9}}}
{{{(18+9*sqrt(7))/9}}}  Factor out a 9 in the numerator.
{{{9(2+sqrt(7))/9}}} Cancel the 9's
{{{cross(9)(2+sqrt(7))/cross(9)}}}
{{{highlight(2+sqrt(7))}}}
Happy Calculating!!!