Question

1/(1- radical din 2) - 7/(3- radical din 2 )+ radical din 8

Answer 1

$\frac{1+ \sqrt{2} }{1-2}- \frac{7(3+ \sqrt{2)} }{9-2} + 2\sqrt{2}$
$\sqrt{2} -1- \frac{7(3+ \sqrt{2)} }{7} +2 \sqrt{2}$
3$\sqrt{2} -1- \frac{7(3+ \sqrt{2)} }{7}$
$3 \sqrt{2} -1-3- \sqrt{2} = 2\sqrt{2} -4=2( \sqrt{2} -2)$