Bài 29:
a) \(\dfrac{\sqrt{2}}{\sqrt{18}}=\sqrt{\dfrac{2}{18}}=\sqrt{\dfrac{1}{9}}=\dfrac{1}{3}\)
b) \(=\sqrt{\dfrac{12500}{500}}=\sqrt{25}=5\)
Bài 30:
a) \(=\dfrac{y}{x}.\dfrac{\left|x\right|}{y^2}=\dfrac{y}{x}.\dfrac{x}{y^2}=\dfrac{1}{y}\)
b) \(=2y^2.\dfrac{x^2}{2\left|y\right|}=2y^2.\dfrac{x^2}{-2y}=-x^2y\)