[tex]\frac{5}{\sqrt{7}}=\frac{5.\sqrt{7}}{\sqrt{7}.\sqrt{7}}= \frac{5.\sqrt{7}}{7} [/tex]
[tex]\frac{3}{6\sqrt{2}}= \frac{1}{2\sqrt{2}}=\frac{\sqrt{2}}{2.2}=\frac{\sqrt{2}}{4}[/tex][tex]\frac{2\sqrt{3}}{5\sqrt{2}}=\frac{2.\sqrt{3}.\sqrt{2}}{5.2}=\frac{\sqrt{6}}{5}[/tex]
[tex]\frac{3+\sqrt{2}}{\sqrt{2}}=\frac{(3+\sqrt{2}).\sqrt{2}}{\sqrt{2}.\sqrt{2}} = \frac{3\sqrt{2}+2}{2}[/tex]
f(-2) = (-6+1/3)/2 = -17/6
f(2/5) = (6/5+1/3)/2 = 23/30
