` \sqrt49 + \sqrt25 - 4\sqrt(0,25)`
`= 7 + 5 - 2`
`= 10`
`(\sqrt109 - \sqrt121 - \sqrt81) : \sqrt(0,49)`
`= (\sqrt109 - 11 - 9) : 0,7`
`= (\sqrt109 - 20) : 0,7`
`= (10\sqrt109)/7 - 200/7`
`= (10\sqrt109 - 200)/7`
`\sqrt(1/9) . \sqrt(0,81) . \sqrt(0,09)`
`= 1/3 . 0,9 . 0,3`
`= 0,09`
`3/5 . \sqrt16 + 2\sqrt(16/25)`
`= 3/5 . 4 + 2. 4/5`
`= 12/5 + 8/5`
`= 4`