Đáp án+Giải thích các bước giải:
`\sqrt{2-\sqrt{3}}-\sqrt{2+\sqrt{3}}`
`=(\sqrt{2}.(\sqrt{2-\sqrt{3}}-\sqrt{2+\sqrt{3}}))/(\sqrt{2})`
`=(\sqrt{2}.\sqrt{2-\sqrt{3}}-\sqrt{2}.\sqrt{2+\sqrt{3}})/(\sqrt{2})`
`=(\sqrt{4-2\sqrt{3}}-\sqrt{4+2\sqrt{3}})/(\sqrt{2})`
`=(\sqrt{3-2\sqrt{3}+1}-\sqrt{3+2\sqrt{3}+1})/(\sqrt{2})`
`=(\sqrt{(\sqrt{3}-1)^2}-\sqrt{(\sqrt{3}+1)^2})/(\sqrt{2})`
`=(|\sqrt{3}-1|-|\sqrt{3}+1|)/(\sqrt{2})`
`=(\sqrt{3}-1-\sqrt{3}-1)/(\sqrt{2})(Vì:\sqrt{3}>1)`
`=(-2)/(\sqrt{2})=-\sqrt{2}`
