Question

Racionalize os denominadores de cada uma destas expressões:

a) 3/√11 =

b) 3/2-√5 =

Answer 1

$a) \frac{3}{\sqrt{11}} =\frac{3}{\sqrt{11}}\cdot\frac{\sqrt{11}}{\sqrt{11}}= \frac{3 \sqrt{11}}{ \sqrt{121}}= \frac{3 \sqrt{11} }{11}\\ \\ b)\frac{3}{2- \sqrt{5}} =\frac{3}{2- \sqrt{5}} \cdot\frac{2+ \sqrt{5}}{2+ \sqrt{5}}= \frac{3(2- \sqrt{5})}{2^2-( \sqrt{5} )^2}= \frac{3(2- \sqrt{5})}{4-5}= \frac{3(2- \sqrt{5})}{1}=6- 3\sqrt{5}$