2. a) [tex]2\sqrt{3}+5\sqrt{3}-8\sqrt{3} = 8\sqrt{3}-8\sqrt3= 0[/tex]
b)[tex]-\sqrt{5} +5\sqrt{5} -(-8\sqrt{5}) = 4\sqrt{5}+8\sqrt{5} = 12\sqrt{5}[/tex]
c) [tex]0,5\sqrt{7}+5,5\sqrt{7}-9\sqrt{3} = 6\sqrt{7}-9\sqrt{3}[/tex]
3. a)[tex]4\sqrt{3}+5\sqrt{7} -5\sqrt{3}+2\sqrt{7} = 7\sqrt{7}-\sqrt{3}[/tex]
b)[tex]-42\sqrt{3} +15\sqrt{2}-18\sqrt{2}+9\sqrt{3} = -33\sqrt{3}-3\sqrt{2}[/tex]
c)[tex]-2\sqrt{3} -(-\sqrt{12} -6\sqrt{3}) = -2\sqrt{3}+2\sqrt{3}+6\sqrt{3} = 4\sqrt{3} +2\sqrt{3}= 6\sqrt{3}[/tex]
