a)[tex]x\sqrt{\frac{11}{x}}=\sqrt{\frac{11}{x}.x^{2}}=\sqrt{11x}[/tex] ; b)[tex]x.\sqrt{\frac{-29}{x}}=-\left | x \right |.\sqrt{\frac{29}{\left | x \right |}}=-\sqrt{\frac{29}{\left | x \right |}.x^{2}}=-\sqrt{29\left | x \right |}[/tex]
P/s:Thấy hay thì 1 like thay lời cảm ơn nhé