Question 50

Jambmaths question: 

Rationalize $\frac{2}{6-5\sqrt{3}}$

Option A: 

$-\tfrac{12}{39}-\tfrac{10\sqrt{3}}{39}$

Option B: 

$\tfrac{12}{39}-\tfrac{10\sqrt{3}}{39}$

Option C: 

$-\tfrac{12}{39}+\tfrac{10\sqrt{3}}{39}$

Option D: 

$\tfrac{12}{39}+\tfrac{10\sqrt{3}}{39}$

Jamb Maths Solution: 

$\begin{align}  & \frac{2}{6-5\sqrt{3}}=\frac{2}{6-5\sqrt{3}}\times \frac{6+5\sqrt{3}}{6+5\sqrt{3}} \\ & =\frac{2(6+5\sqrt{3)}}{36-75}=\frac{2(6+5\sqrt{3})}{-39} \\ & =-\frac{12}{39}-\frac{10\sqrt{3}}{39} \end{align}$

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