Question

⁴√16-6³√343+18×√243-√196

Answer 1

$=2 - 6 \times \sqrt{7 \times 49} + 18 \times \sqrt{81}$
-14

$= 2 - 6 \times 7 \sqrt{7} + 162 - 14$

$= 2 - 42 \sqrt{7} + 148 \\ = 150 - 42 \sqrt{7} \\ = 2(75 - 21 \sqrt{7} )$