Tìm TXĐ? Rút gọn B

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3) B = $\left(\frac{2\sqrt{x}}{\sqrt{x+3}} - \frac{\sqrt{x}}{3-\sqrt{x}} - \frac{3x+3}{x-9}\right)$, $\left(\frac{2x+4}{\sqrt{x+3}} - 1\right)$

c) $\\ \{x \in \mathbb{R}; x \geq 2\}$
a) $\\ \{x \in \mathbb{R}; x \neq 2\}$
b) $\\ \{x \in \mathbb{R}; x \geq 2\}$