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JAMB Mathematics 2021 Paper

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Question : 14

Total: 40

Simplify

\sqrt{27}

\frac{3}{\sqrt{3}}

4 $\sqrt{3}$
$\frac{4}{\sqrt{3}}$
3 $\sqrt{3}$
$\frac{\sqrt{3}}{4}$

Solution:

Concept:

Simplify each radical term first, then add like surds.

Explanation:

Write

\sqrt{27}

as

\sqrt{9 \times 3}

.

Since

\sqrt{9} = 3

, this gives

3\sqrt{3}

.

Rationalise

\frac{3}{\sqrt{3}}

by multiplying numerator and denominator by

\sqrt{3}

:

\frac{3}{\sqrt{3}} \times \frac{\sqrt{3}}{\sqrt{3}} = \frac{3\sqrt{3}}{3} = \sqrt{3}

.

Now add the two terms:

3\sqrt{3} + \sqrt{3} = 4\sqrt{3}

.

Answer:

4\sqrt{3}

Correct option: A.

4\sqrt{3}

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