a)
[tex]f(x) = \sqrt{x^{2}-16}\\\\\sqrt{x^{2}-16} \geq 0\\\\x^{2}-16 \geq 0\\\\(x+4)(x-4) = 0\\\\x+4 = 0 \ \vee \ x-4 = 0\\\\x = -4 \ \vee \ x = 4\\\\a > 0, \ to \ ramiona \ wykresu \ paraboli \ skierowane \ do \ gory, \ wowczas:\\\\\underline{D: \ x\in(-\infty;-4\rangle \ \cup \ \langle4:+\infty)}[/tex]
b)
[tex]f(x)=\sqrt{x^{2}-4x+3}\\\\\sqrt{x^{2}-4x+3} \geq 0\\\\x^{2}-4x+3\geq 0\\\\M. \ zerowe:\\\\x^{2}-3x-x+3 = 0\\\\x(x-3)-(x-3) = 0\\\\(x-1)(x-3) = 0\\\\x-1 = 0 \ \vee \ x-3 = 0\\\\x = 1 \ \vee \ x = 3\\\\a > 0, \ to \ ramiona \ wykresu \ paraboli \ skierowane \ do \ gory, \ wowczas:\\\\\underline{D: \ x \in(-\infty;1\rangle \ \cup \ \langle3;+\infty)}[/tex]
