Question

Đã trả lời bởi chuyên gia

Answer 1

a,

$\sqrt{3 x - 54} c ó n g h ĩ a k h i : 3 x - 54 \geq 0 \Rightarrow x \geq 18 b, \sqrt{15 - 2 x} c ó n g h ĩ a k h i : 15 - 2 x \geq 0 \Rightarrow 2 x \leq 15 \Rightarrow x \leq \frac{15}{2} c, \frac{x}{x + 5} c ó n g h ĩ a k h i : x + 5 # 0 \Rightarrow x # - 5 d, \frac{5 x}{\sqrt{15 - 3 x}} c ó n g h ĩ a k h i : 15 - 3 x > 0 \Rightarrow 3 x < 15 \Rightarrow x < 5 e, \frac{4}{\sqrt{2 x - 4}} c ó n g h ĩ a k h i : 2 x - 4 > 0 \Rightarrow x > 2 f, \sqrt{x} . \frac{x}{2 \sqrt{3 x - 5}} c ó n g h ĩ a k h i : \{\begin{array}{l} x \geq 0 \\ 3 x - 5 > 0 \end{array} \Rightarrow \{\begin{array}{l} x \geq 0 \\ x > \frac{5}{3} \end{array} \Rightarrow x > \frac{5}{3}$

$g, \sqrt{x + 3} . \frac{1}{x - 5} c ó n g h ĩ a k h i : \{\begin{array}{l} x + 3 \geq 0 \\ x - 5 # 0 \end{array} \Rightarrow \{\begin{cases} x \geq - 3 \\ x # 5 \end{cases} h, \sqrt{18 - 2 x} c ó n g h ĩ a k h i : 18 - 2 x \geq 0 \Rightarrow 2 x \leq 18 \Rightarrow x < 9 k, \sqrt{12 - 4 x} c ó n g h ĩ a k h i : 12 - 4 x \geq 0 \Rightarrow 4 x \leq 12 \Rightarrow x \leq 3 m, \sqrt{2 x + 9} c ó n g h ĩ a k h i : 2 x + 9 \geq 0 \Rightarrow x \geq \frac{- 9}{2} n, \sqrt{x + 3} . \sqrt{2 x - 4} c ó n g h ĩ a k h i : \{\begin{array}{l} x + 3 \geq 0 \\ 2 x - 4 \geq 0 \end{array} \Rightarrow \{\begin{array}{l} x \geq - 3 \\ x \geq 2 \end{array} \Rightarrow x \geq 2$

$o, \frac{2 \sqrt{3 x + 4}}{\sqrt{15 - 3 x}} c ó n g h ĩ a k h i : \{\begin{array}{l} 3 x + 4 \geq 0 \\ 15 - 3 x > 0 \end{array} \Rightarrow \{\begin{cases} x \geq \frac{- 4}{3} \\ x < 5 \end{cases} \Rightarrow \frac{- 4}{3} \leq x < 5 p, \frac{\sqrt{5 x + 4}}{x - 1} c ó n g h ĩ a k h i : \{\begin{array}{l} 5 x + 4 \geq 0 \\ x - 1 # 0 \end{array} \Rightarrow \{\begin{cases} x \geq \frac{- 4}{5} \\ x # 1 \end{cases} q, \frac{x}{\sqrt{x - 1}} + \frac{3}{\sqrt{x + 1}} c ó n g h ĩ a k h i : \{\begin{array}{l} x - 1 > 0 \\ x + 1 > 0 \end{array} \Rightarrow \{\begin{cases} x > 1 \\ x > - 1 \end{cases} \Rightarrow x > 1 r, \frac{3}{5 \sqrt{x - 15}} c ó n g h ĩ a k h i : x - 15 > 0 \Rightarrow x > 15$

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Answer 2

a,

$\sqrt{3 x - 54} c ó n g h ĩ a k h i : 3 x - 54 \geq 0 \Rightarrow x \geq 18 b, \sqrt{15 - 2 x} c ó n g h ĩ a k h i : 15 - 2 x \geq 0 \Rightarrow 2 x \leq 15 \Rightarrow x \leq \frac{15}{2} c, \frac{x}{x + 5} c ó n g h ĩ a k h i : x + 5 # 0 \Rightarrow x # - 5 d, \frac{5 x}{\sqrt{15 - 3 x}} c ó n g h ĩ a k h i : 15 - 3 x > 0 \Rightarrow 3 x < 15 \Rightarrow x < 5 e, \frac{4}{\sqrt{2 x - 4}} c ó n g h ĩ a k h i : 2 x - 4 > 0 \Rightarrow x > 2 f, \sqrt{x} . \frac{x}{2 \sqrt{3 x - 5}} c ó n g h ĩ a k h i : \{\begin{array}{l} x \geq 0 \\ 3 x - 5 > 0 \end{array} \Rightarrow \{\begin{array}{l} x \geq 0 \\ x > \frac{5}{3} \end{array} \Rightarrow x > \frac{5}{3}$

$g, \sqrt{x + 3} . \frac{1}{x - 5} c ó n g h ĩ a k h i : \{\begin{array}{l} x + 3 \geq 0 \\ x - 5 # 0 \end{array} \Rightarrow \{\begin{cases} x \geq - 3 \\ x # 5 \end{cases} h, \sqrt{18 - 2 x} c ó n g h ĩ a k h i : 18 - 2 x \geq 0 \Rightarrow 2 x \leq 18 \Rightarrow x < 9 k, \sqrt{12 - 4 x} c ó n g h ĩ a k h i : 12 - 4 x \geq 0 \Rightarrow 4 x \leq 12 \Rightarrow x \leq 3 m, \sqrt{2 x + 9} c ó n g h ĩ a k h i : 2 x + 9 \geq 0 \Rightarrow x \geq \frac{- 9}{2} n, \sqrt{x + 3} . \sqrt{2 x - 4} c ó n g h ĩ a k h i : \{\begin{array}{l} x + 3 \geq 0 \\ 2 x - 4 \geq 0 \end{array} \Rightarrow \{\begin{array}{l} x \geq - 3 \\ x \geq 2 \end{array} \Rightarrow x \geq 2$

$o, \frac{2 \sqrt{3 x + 4}}{\sqrt{15 - 3 x}} c ó n g h ĩ a k h i : \{\begin{array}{l} 3 x + 4 \geq 0 \\ 15 - 3 x > 0 \end{array} \Rightarrow \{\begin{cases} x \geq \frac{- 4}{3} \\ x < 5 \end{cases} \Rightarrow \frac{- 4}{3} \leq x < 5 p, \frac{\sqrt{5 x + 4}}{x - 1} c ó n g h ĩ a k h i : \{\begin{array}{l} 5 x + 4 \geq 0 \\ x - 1 # 0 \end{array} \Rightarrow \{\begin{cases} x \geq \frac{- 4}{5} \\ x # 1 \end{cases} q, \frac{x}{\sqrt{x - 1}} + \frac{3}{\sqrt{x + 1}} c ó n g h ĩ a k h i : \{\begin{array}{l} x - 1 > 0 \\ x + 1 > 0 \end{array} \Rightarrow \{\begin{cases} x > 1 \\ x > - 1 \end{cases} \Rightarrow x > 1 r, \frac{3}{5 \sqrt{x - 15}} c ó n g h ĩ a k h i : x - 15 > 0 \Rightarrow x > 15$

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