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Indices & Surds

10 exam-style questions on laws of indices, negative and fractional indices, and simplifying surds.

4 Easy 4 Medium 2 Hard
Q1Easy2 marks

Simplify \( a^3 \times a^5 \).

\( a^8 \).

Q2Easy2 marks

Simplify \( \dfrac{x^7}{x^2} \).

\( x^5 \).

Q3Easy2 marks

Evaluate \( 2^{-3} \).

\( \dfrac{1}{2^3} = \dfrac{1}{8} \).

Q4Easy2 marks

Simplify \( \sqrt{50} \).

\( \sqrt{25 \times 2} = 5\sqrt{2} \).

Q5Medium3 marks

Simplify \( (3x^2)^3 \).

\( 27x^6 \).

Q6Medium3 marks

Evaluate \( 16^{3/4} \).

\( (16^{1/4})^3 = 2^3 = 8 \), or \( (16^3)^{1/4} \).

Q7Medium4 marks

Simplify \( \sqrt{18} + \sqrt{8} \).

\( 3\sqrt{2} + 2\sqrt{2} = 5\sqrt{2} \).

Q8Medium4 marks

Rationalise the denominator of \( \dfrac{5}{\sqrt{2}} \).

\( \dfrac{5}{\sqrt{2}} \times \dfrac{\sqrt{2}}{\sqrt{2}} = \dfrac{5\sqrt{2}}{2} \).

Q9Hard5 marks

Simplify \( \dfrac{6}{\sqrt{3} + 1} \) by rationalising the denominator.

Multiply by \( \sqrt{3}-1 \): \( \dfrac{6(\sqrt{3}-1)}{3-1} = \dfrac{6(\sqrt{3}-1)}{2} = 3(\sqrt{3}-1) \).

Q10Hard5 marks

Simplify \( (2\sqrt{3} + 1)(2\sqrt{3} - 1) \).

Difference of squares: \( (2\sqrt{3})^2 - 1^2 = 12 - 1 = 11 \).