The rationalisation factor of 1 23-5 is: - Vidyadip

MCQ

The rationalisation factor of $\frac{1}{2\sqrt{3}-\sqrt{5}}$ is:

A
$(\sqrt{3}+\sqrt{5})$
B
$\sqrt{12}+\sqrt{5}$
C
$\sqrt{5}-2\sqrt{3}$
D
$\sqrt{3}+2\sqrt{5}$

✓

Answer

$\sqrt{12}+\sqrt{5}$

Solution:
$\frac{1}{2\sqrt{3}-\sqrt{5}}$
$=(2\sqrt{3}-\sqrt{5})(2\sqrt{3}+\sqrt{5})$
$=12-5$
$=7$
Rational number
$(2\sqrt{3}+\sqrt{5})=(\sqrt{4\times3}+\sqrt{5})=\sqrt{12}+\sqrt{5}$

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