2 câu trả lời
`#tnvt`
`\sqrt{810.40}`
`=\sqrt{81.10.4.10}`
`=\sqrt{9^2 .10^2 .2^2}`
`=\sqrt{9^2}.\sqrt{10^2}.\sqrt{2^2}`
`=|9|.|10|.|2|`
`=9.10.2`
`=18.10`
`=180`
`\sqrt{810.40}`
`=\sqrt{81.10.4.10}`
`=\sqrt{9^2 . 10^2 . 2^2}`
`=|9|.|10|.|2|`
`=9.10.2`
`=180`
*Áp dụng công thức: `\sqrt{A^2}=|A|`