[tex] \frac{ \sqrt{400 - 64 \times \sqrt{16} } }{x} = \frac{2 \sqrt{84 + 7 \times {3}^{2} } }{2 \times \frac{1}{4} \times \sqrt{1.(7)} } \\ \frac{ \sqrt{400 - 64 \times 4} }{x} = \frac{2 \sqrt{84 + 7 \times 9} }{ \frac{9}{4} \times \frac{4}{3} } \\ \frac{ \sqrt{400 - 256} }{x} = \frac{2 \sqrt{84 + 63} }{3} \\ \frac{ \sqrt{144} }{x} = \frac{2 \sqrt{147} }{3} \\ \frac{12}{x} = \frac{14 \sqrt{3} }{3} \\ 14 \sqrt{3} x = 36 \\ x = \frac{18}{7 \sqrt{3} } \\ x = \frac{6 \sqrt{3} }{7} [/tex]
