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WAEC Mathematics 2018 Paper

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Question : 2

Total: 50

Evaluate:

\left(64^{\frac{1}{2}} + 125^{\frac{1}{3}}\right)^2

121
144
169
196

Solution:

Concept:

Fractional exponents represent roots. Evaluate each root first, then add, then square.

Explanation:

Rewrite the fractional powers as roots:

64^{\frac{1}{2}} = \sqrt{64} = 8

125^{\frac{1}{3}} = \sqrt[3]{125} = 5

Add the two values:

8 + 5 = 13

Square the sum:

13^2 = 169

Therefore,

\left(64^{\frac{1}{2}} + 125^{\frac{1}{3}}\right)^2 = 169

.

Answer:

169

, i.e. Option C.

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