Cześć ;-)
a)
[tex]\sqrt{12}+\sqrt{27}-\sqrt{75}=\sqrt{4\cdot3}+\sqrt{9\cdot3}-\sqrt{25\cdot3}=\\\\=\sqrt{2^2\cdot3}+\sqrt{3^2\cdot3}-\sqrt{5^2\cdot3}=\\\\=2\sqrt3+3\sqrt3-5\sqrt3=5\sqrt3-5\sqrt3=\boxed0[/tex]
b)
[tex]3\sqrt{80}-\sqrt{45}-2\sqrt{125}=3\sqrt{16\cdot5}-\sqrt{9\cdot5}-2\sqrt{25\cdot5}=\\\\=3\sqrt{4^2\cdot5}-\sqrt{3^2\cdot5}-2\sqrt{5^2\cdot5}=\\\\=3\cdot4\sqrt5-3\sqrt5-2\cdot5\sqrt5=12\sqrt5-3\sqrt5-10\sqrt5=\boxed{-\sqrt5}[/tex]
Pozdrawiam!
