140, to\; \; \sqrt{196}>\sqrt{140}\; \to \; 14>\sqrt{140}\\\\\\\frac{1}{7+4\sqrt3}+\frac{1}{7-4\sqrt3}>\sqrt{140}" alt="\frac{1}{7+4\sqrt3}+\frac{1}{7-4\sqrt3}=\frac{7-4\sqrt3+7+4\sqrt3}{(7+4\sqrt3)(7-4\sqrt3)}=\frac{14}{49-16\cdot 3}=14\\\\14^2=196\; \to \; \sqrt{196}=14\\\\T.k.\; 196>140, to\; \; \sqrt{196}>\sqrt{140}\; \to \; 14>\sqrt{140}\\\\\\\frac{1}{7+4\sqrt3}+\frac{1}{7-4\sqrt3}>\sqrt{140}" align="absmiddle" class="latex-formula">