Toán ________ 1. √14-6 √5 ________ 2. √16-6 √7 16/07/2021 By Kennedy ________ 1. √14-6 √5 ________ 2. √16-6 √7
Đáp án+Giải thích các bước giải: `1)` `\sqrt{14-6\sqrt5}` `=\sqrt{9-6\sqrt5+5}` `=\sqrt{3^2-2.3.\sqrt5+(\sqrt5)^2}` `=\sqrt{(3-\sqrt5)^2}` `=|3-\sqrt5|` `=3-\sqrt5` `2)` `\sqrt{16-6\sqrt7}` `=\sqrt{9-6\sqrt7+7}` `=\sqrt{3^2-2.3.\sqrt7+(\sqrt7)^2}` `=\sqrt{(3-\sqrt7)^2}` `=|3-\sqrt7|` `=3-\sqrt7` Trả lời
`1)sqrt{14-6sqrt5}` `=sqrt{9-2.3.sqrt5+5}` `=sqrt{(3-sqrt5)^2}` `=|3-sqrt5|` `=3-sqrt5` `2)sqrt{16-6sqrt7}` `=sqrt{9-2.3.sqrt7+7}` `=sqrt{(3-sqrt7)^2}` `=|3-sqrt7|` `=3-sqrt7`. Trả lời
Đáp án+Giải thích các bước giải:
`1)`
`\sqrt{14-6\sqrt5}`
`=\sqrt{9-6\sqrt5+5}`
`=\sqrt{3^2-2.3.\sqrt5+(\sqrt5)^2}`
`=\sqrt{(3-\sqrt5)^2}`
`=|3-\sqrt5|`
`=3-\sqrt5`
`2)`
`\sqrt{16-6\sqrt7}`
`=\sqrt{9-6\sqrt7+7}`
`=\sqrt{3^2-2.3.\sqrt7+(\sqrt7)^2}`
`=\sqrt{(3-\sqrt7)^2}`
`=|3-\sqrt7|`
`=3-\sqrt7`
`1)sqrt{14-6sqrt5}`
`=sqrt{9-2.3.sqrt5+5}`
`=sqrt{(3-sqrt5)^2}`
`=|3-sqrt5|`
`=3-sqrt5`
`2)sqrt{16-6sqrt7}`
`=sqrt{9-2.3.sqrt7+7}`
`=sqrt{(3-sqrt7)^2}`
`=|3-sqrt7|`
`=3-sqrt7`.