Bạn tham khảo nhé.
`(3+\sqrt{5})(\sqrt{2}-\sqrt{10})\sqrt{3-\sqrt{5}}`
`=(3+\sqrt{5})(1-\sqrt{5}).\sqrt{2}.\sqrt{3-\sqrt{5}}`
`=(3+\sqrt{5})(1-\sqrt{5}).\sqrt{6-2\sqrt{5}}`
`=(3+\sqrt{5})(1-\sqrt{5}).\sqrt{5-2\sqrt{5}+1}`
`=(3+\sqrt{5})(1-\sqrt{5}).\sqrt{(\sqrt{5}-1)^2}`
`=(3+\sqrt{5})(1-\sqrt{5})|\sqrt{5}-1|`
`=-(3+\sqrt{5})(\sqrt{5}-1)(\sqrt{5}-1)`
`=-(3+\sqrt{5})(5-2\sqrt{5}+1)`
`=-(3+\sqrt{5})(6-2\sqrt{5})`
`=-2(3+\sqrt{5})(3-\sqrt{5})`
`=-2(3^2-\sqrt{5}^2)`
`=-2(9-5)`
`=-2.4`
`=-8`
