Đáp án:Đề bài bạn ghi khó hiểu quá.
`H=\sqrt{4/(2-sqrt5)^2}-sqrt{4/(2+sqrt5)^2}`
`=2/(sqrt5-2)-2/(sqrt5+2)`
`=(2(sqrt5+2))/(5-4)-(2(sqrt5-2))/(5-4)`
`=2(sqrt5+2)-2(sqrt5-2)`
`=2sqrt5+4-2sqrt5+4`
`=8`
`I=(sqrt{10}-sqrt2)/(sqrt5-1)-(2-sqrt2)/(sqrt2-1)`
`=(sqrt2(sqrt5-1))/(sqrt5-1)-(sqrt2(sqrt2-1))/(sqrt2-1)`
`=sqrt2-sqrt2=0`
`K=2/(2-sqrt5)-2/(2+sqrt5)`
`=(2(sqrt5+2))/(4-5)-(2(sqrt5-2))/(5-4)`
`=-2(sqrt5+2)-2(sqrt5-2)`
`=-4-2sqrt5-2sqrt5+4`
`=-4sqrt5`.