If \(K\sqrt{28}+\sqrt{63}-\sqrt{7}=0\), find K.

  • A -2
  • B -1
  • C 1
  • D 2
waec 1999mathematics

The correct answer is B. -1

\(K\sqrt{28}+\sqrt{63}-\sqrt{7}=0\\

2K\sqrt{7}+3\sqrt{7}-\sqrt{7}=0\\

2K\sqrt{7}=-2\sqrt{7}\\

K=\frac{-2\sqrt{7}}{2\sqrt{7}}\\

K=-1\)

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