June 2019 Paper 1 Q5

5 Solve \(\quad \sqrt[3]{\left(2\sqrt{x} - 10\right)} = 2\) [3 marks]

Mark scheme

Answer	Mark	Comments
\(2\sqrt{x} - 10 = 2^3\) or \(2\sqrt{x} - 10 = 8\) or \(2\sqrt{x} = 18\)	M1
\(\sqrt{x} = \dfrac{2^3+10}{2}\) or \(\sqrt{x} = \dfrac{8+10}{2}\) or \(\sqrt{x} = 9\) or \(4x = 18^2\) or \(x = 9^2\)	M1dep
\(x = 81\)	A1	\(\pm 81\) scores A0