Question

determine o valor de X

$\sqrt{21 + \sqrt{13 + \sqrt{7 + \sqrt{4 = } } } }$
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Answer 1

$x=\sqrt{21+\sqrt{13+\sqrt{7+\sqrt{4}}}}\\\\x=\sqrt{21+\sqrt{13+\sqrt{7+2}}}\\\\x=\sqrt{21+\sqrt{13+\sqrt{9}}}\\\\x=\sqrt{21+\sqrt{13+3}}\\\\x=\sqrt{21+\sqrt{16}}\\\\x=\sqrt{21+4}\\\\x=\sqrt{25}\\\\x=5$