Express \(\frac{8 - 3\sqrt{6}}{2\sqrt{3} + 3\sqrt{2}}\) in the form \(p\sqrt{3} + q\sqrt{2}\).

  • A \(7\sqrt{3} - \frac{17\sqrt{2}}{3}\)
  • B \(7\sqrt{2} - \frac{17\sqrt{3}}{3}\)
  • C \(-7\sqrt{2} + \frac{17\sqrt{3}}{3}\)
  • D \(-7\sqrt{3} - \frac{17\sqrt{2}}{3}\)
waec 2016furthermathematics

The correct answer is B. \(7\sqrt{2} - \frac{17\sqrt{3}}{3}\)

Given \(\frac{8 - 3\sqrt{6}}{2\sqrt{3} + 3\sqrt{2}}\),

first, we rationalise  by multiplying through with \(2\sqrt{3} - 3\sqrt{2}\) (the inverse of the denominator).

\((\frac{8 - 3\sqrt{6}}{2\sqrt{3} + 3\sqrt{2}})(\frac{2\sqrt{3} - 3\sqrt{2}}{2\sqrt{3} - 3\sqrt{2}})\)

= \(\frac{16\sqrt{3} - 24\sqrt{2} - 18\sqrt{2} + 18\sqrt{3}}{4(3) - 6\sqrt{6} + 6\sqrt{6} - 9(2)}\)

= \(\frac{34\sqrt{3} - 42\sqrt{2}}{-6} = 7\sqrt{2} - \frac{17\sqrt{3}}{3}\)

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