Question

√(6-√7)2 - √(√7-3)2.

Answer 1

$\sqrt{(6- \sqrt{7} )^2} - \sqrt{(\sqrt{7}-3 )^2} = |6- \sqrt{7} | - |\sqrt{7}-3 |=\\ = (6- \sqrt{7} ) - (3-\sqrt{7})=6-3=3$

Answer 2

$\sqrt{(6- \sqrt{7} )^2} - \sqrt{( \sqrt{7}-3)^2 } =|6- \sqrt{7} -| \sqrt{7} -3|=$$6- \sqrt{7} -(3- \sqrt{7} )=6- \sqrt{7} -3+ \sqrt{7} =3$