p/s: ... (phuonglenhat123) ăn nói cho hẳn hoi vs mk nhắc bn thêm lần nx
a) \(\frac{2}{4-3\sqrt{2}}-\frac{2}{4+3\sqrt{2}}\)
\(=\frac{2\left(4+3\sqrt{2}\right)-2\left(4-3\sqrt{2}\right)}{\left(4-3\sqrt{2}\right)\left(4+3\sqrt{2}\right)}\)
\(=\frac{2\left(4+3\sqrt{2}-4+3\sqrt{2}\right)}{16-18}\)
\(=\frac{12\sqrt{2}}{-2}=-6\sqrt{2}\)
b) ĐKXĐ :\(x\ge0\)
\(\sqrt{2x}-\sqrt{50}=0\)
\(\Leftrightarrow\sqrt{2x}=\sqrt{50}\)
\(\Leftrightarrow2x=50\)
\(\Leftrightarrow x=25\left(Tm\right)\)
a) \(\frac{2}{4-3\sqrt{2}}-\frac{2}{4+3\sqrt{2}}\)
\(=\frac{2\left(4+3\sqrt{2}\right)}{\left(4-3\sqrt{2}\right)\left(4+3\sqrt{2}\right)}-\frac{2\left(4-3\sqrt{2}\right)}{\left(4+3\sqrt{2}\right)\left(4-3\sqrt{2}\right)}\)
\(=\frac{2\left(4+3\sqrt{2}\right)-2\left(4-3\sqrt{2}\right)}{-2}\)
\(=\frac{12\sqrt{2}}{-2}\)
\(=-6\sqrt{2}\)
b) ĐKXĐ: \(x\ge0\)
\(\sqrt{2x}-\sqrt{50}=0\)
\(\sqrt{2x}-5\sqrt{2}=0\)
\(\sqrt{2x}=0+5\sqrt{2}\)
\(\sqrt{2x}=5\sqrt{2}\)
\(2x=50\)
\(x=50:2\)
\(x=25\left(tm\right)\)
