Объяснение:
А) f(x) = 3/(x^2-4)
x²-4≠0
(x-2)(x+2)≠0
x≠ 2 ; -2 иначе x≠±2
x∈(-∞;-2)∨(-2;2)∨(2;+∞)
B) f(x) = sqrt(-x)/(3x^2-6) - измененное : (√-x)/(3x²-6)
{-x≥0 {- система
{3x²-6≠0
{x≤0
{3(x²-2)≠0
{x≤0 ⇒ {x≤0 ⇒{ x≤0
{x²-2≠0 {(x-√2)(x+√2)≠0 {x≠ √2 ; -√2 иначе x≠±√2
x∈(-∞;-√2)∪(-√2;0]
![\displaystyle\\A) f(x)=\frac{3}{x^2-4}\\\\ x^2-4\neq 0\\\\x^2\neq 4\\\\x\neq \pm 2\\\\x\in (-\infty;-2)\cup(-2;2)\cup(2;+\infty)\\\\B) f(x)=\frac{\sqrt{-x}}{3x^2-6} \\\\\left \{ {{x\leq 0} \atop {3x^2-6\neq 0}} \right.\\\\\\ 3x^2\neq6\\\\ x^2\neq 2\\\\x\neq \pm\sqrt{2}\\\\x\in(-\infty;-\sqrt{2})\cup(-\sqrt{2};0]](/tpl/images/1353/8859/ba4c8.png)
