3)
[tex]perimetru = \sqrt{2} +1 + 3 - \sqrt{2} + 1 \\ perimetru = 1+ 3 + 1 = 5[/tex]
4)
[tex] |3 - 2 \sqrt{5} | = | \sqrt{9} - \sqrt{20} | \\ 9 < 20 \\ | \sqrt{9 } - \sqrt{20} | = - (3 - \sqrt{20} ) \\ - 3 + 2 \sqrt{5} [/tex]
