Question

Rationalizati $\frac{ 6}{ \sqrt{11} +5}$

Answer 1

$\displaystyle \frac{6}{ \sqrt{11} +5} = \frac{6( \sqrt{11}-5) }{11-25} = \frac{6 \sqrt{11} -30}{-14} = \frac{2(3 \sqrt{11} -15)}{-14} = \\ \\ = \frac{3 \sqrt{11} -15}{-7} =- \frac{3 \sqrt{11} -15}{7}$