Bài tập 1:
` a) ` ` \sqrt{\frac{289}{225}} `
` = \frac{\sqrt{17^2}}{\sqrt{15^2}} `
` = \frac{17}{15} `
` b) ` ` \sqrt{\frac{0,25}{9}} `
` = \sqrt{(\frac{1}{2})^2} : \sqrt{3^2} `
` = \frac{1}{2} : 3 `
` = \frac{1}{2} . 1/3 `
` = 1/6 `
` c) ` ` \frac{\sqrt{2}}{\sqrt{18}} `
` = \sqrt{\frac{2}{2.9}} `
` = \sqrt{\frac{1}{9}} `
` = 1/3 `
` d) ` ` \frac{\sqrt{15}}{\sqrt{735}} `
` = \sqrt{\frac{15}{15.49}} `
` = \sqrt{\frac{1}{49}} `
` = 1/7 `
Bài tập 2:
` a) ` ` \sqrt{\frac{2a^2 b^4}{50}} `
` = \sqrt{\frac{a^2 b^4}{25}} `
` = \frac{\sqrt{(ab^2)^2}}{\sqrt{5^2}} `
` = \frac{ab^2}{5} `
` b) ` ` \frac{\sqrt{2ab^2}}{\sqrt{162}} ` ` (a ≥ 0) `
` = \sqrt{\frac{2ab^2}{2.81}} `
` = \sqrt{\frac{ab^2}{81}} `
` = \frac{\sqrt{a}.\sqrt{b^2}}{\sqrt{9^2}} `
` = \frac{b\sqrt{a}}{9} `
` c) ` ` y/x . \sqrt{\frac{x^2}{y^2}} ` ` (x > 0, y ne 0) `
` = y/x . \frac{\sqrt{x^2}}{\sqrt{y^2}} `
` = y/x . \frac{x}{y} `
` = 1 `
