Bentuk rasional dari 4 per akar 27 + akar 12 adalah...

[tex]\displaystyle \frac{4}{\sqrt{27}+\sqrt{12}} = \frac{4}{3\sqrt{3}+2\sqrt{3}} \\ \frac{4}{5\sqrt{3}}=\frac{4}{5\sqrt{3}}\times \frac{\sqrt{3}}{\sqrt{3}} \\ \frac{4\sqrt{3}}{5\times 3}=\frac{4}{15}\sqrt{3}[/tex]