JAMB - Mathematics (2019 - No. 63)

Find the value of k in the equation: \(\sqrt{28} + \sqrt{112} - \sqrt{k} = \sqrt{175}\)
\(\sqrt{28}\)
7
28
\(\sqrt{7}\)

Explanation

\(\sqrt{28} + \sqrt{112} - \sqrt{k} = \sqrt{175}\)

\(\sqrt{4 \times 7} + \sqrt{16 \times 7} - \sqrt{k} = \sqrt{25 \times 7}\)

\(2\sqrt{7} + 4\sqrt{7} - \sqrt{k} = 5\sqrt{7}\)

\(6\sqrt{7} - 5\sqrt{7} = \sqrt{k}\)

\(\sqrt{k} = \sqrt{7}\)

\(\implies k = 7\)

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