[tex]a)\quad |1-\sqrt7| = \sqrt7-1,\quad ($deoarece \sqrt7\ \textgreater \ 1) \\ \\b)\quad |-\sqrt3-\sqrt2| = \sqrt3+\sqrt2\\ \\ c)\quad |8-\sqrt{49}| = |8-7| = |1| = 1\\ \\ d)\quad \underset{(3-\sqrt2)^2\geq0}{\underbrace{\Big|(3-\sqrt2)^2}}\Big| =(3-\sqrt2)^2 = 9-6\sqrt2+2 = 11-6\sqrt2\\[/tex]
