Odpowiedź:
[tex]a)\ \ \frac{3x-5}{(x-3)(x-1)(x+1)}\\\\x-3\neq 0\ \ \ \ i\ \ \ \ x-1\neq 0\ \ \ \ i\ \ \ \ x+1\neq 0\\\\x\neq 3\ \ \ \ i\ \ \ \ x\neq 1\ \ \ \ i\ \ \ \ x\neq -1\\\\D=R\setminus\left\{-1,1,3\right\}\\\\\\b)\ \ \frac{x^5-x^4+\sqrt{3}x^3+3}{(x-\frac{3}{4})(x+7)}\\\\x-\frac{3}{4}\neq 0\ \ \ \ i\ \ \ \ x+7\neq 0\\\\x\neq \frac{3}{4}\ \ \ \ i\ \ \ \ x\neq -7\\\\D=R\setminus\left\{-7,\frac{3}{4}\right\}[/tex]
[tex]c)\ \ \frac{1}{x^2-4}\\\\x^2-4\neq 0\\\\(x-2)(x+2)\neq 0\\\\x-2\neq 0\ \ \ \ i\ \ \ \ x+2\neq 0\\\\x\neq 2\ \ \ \ i\ \ \ \ x\neq -2\\\\D=R\setminus\left\{-2,2\right\}\\\\\\d)\ \ \frac{x}{x^2-2}\\\\x^2-2\neq 0\\\\(x-\sqrt{2})(x+\sqrt{2})\neq 0\\\\x-\sqrt{2}\neq 0\ \ \ \ i\ \ \ \ x+\sqrt{2}\neq 0\\\\x\neq \sqrt{2}\ \ \ \ i\ \ \ \ x\neq -\sqrt{2}\\\\D=R\setminus\left\{-\sqrt{2},\sqrt{2}\right\}[/tex]
[tex]e)\ \ \frac{2x}{x^2-6x+9}\\\\x^2-6x+9\neq 0\\\\(x-3)^2\neq 0\\\\x-3\neq 0\\\\x\neq 3\\\\D=R\setminus\left\{3\right\}[/tex]
