I am trying to help my daughter with this problem
2+square root of 5 over 3 - square root of 6. Please come to my rescue!
In a fraction, you do not keep a surd ($\displaystyle \sqrt{x}$) on the denominator so when it says to simplify the expression, your aim is to remove the surd from the denominator.
$\displaystyle \frac{2+\sqrt{5}}{3-\sqrt{6}}$
Multiply the numerator and the denominator by the conjugate of the denominator which is $\displaystyle 3+\sqrt{6}$
$\displaystyle \left(\frac{2+\sqrt{5}}{3-\sqrt{6}}\right)\left(\frac{3+\sqrt{6}}{3+\sqrt{6} }\right)$
Multiply all the expressions. Numerator with numerator and denominator with denominator.
$\displaystyle =\frac{6 + 2\sqrt{6} + 3\sqrt{5} +\sqrt{30}}{9 + 3\sqrt{6} - 3\sqrt{6} -6}$
$\displaystyle =\frac{6 + 2\sqrt{6} + 3\sqrt{5} +\sqrt{30}}{3}$