Simplify \(\frac{20}{5\sqrt{28} - 2 \sqrt{63}}\)

  • A \(\frac{5\sqrt{7}}{7}\)
  • B \(\frac{5\sqrt{5}}{7}\)
  • C \(\frac{7\sqrt{5}}{7}\)
  • D \(\frac{7\sqrt{7}}{5}\)
waec 2006mathematics

The correct answer is A. \(\frac{5\sqrt{7}}{7}\)

\(\frac{20}{5 \sqrt{4 \times 7} - 2\sqrt{9 \times 7}}\)

\(\frac{20}{10 \sqrt{7} - 6\sqrt{7}}\)

= \(\frac{20 \sqrt{7}}{4 \sqrt{7}}\)

= \(\frac{5\sqrt{7}}{7}\)

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