Đáp án+Giải thích các bước giải:
`c)`
`(\sqrt{18}+\sqrt{32}-\sqrt{50}).\sqrt{2}`
`=(\sqrt{9.2}+\sqrt{16.2}-\sqrt{25.2}).\sqrt{2}`
`=(3\sqrt{2}+4\sqrt{2}-5\sqrt{2}).\sqrt{2}`
`=[(3+4-5).\sqrt{2}].\sqrt{2}`
`=2\sqrt{2}.\sqrt{2}`
`=2.2=4`
`f)`
`\sqrt{50}-\sqrt{18}+\sqrt{200}+\sqrt{162}`
`=\sqrt{25.2}-\sqrt{9.2}+\sqrt{100.2}+\sqrt{81.2}`
`=5\sqrt{2}-3\sqrt{2}+10\sqrt{2}+9\sqrt{2}`
`=(5-3+10+9)\sqrt{2}`
`=21\sqrt{2}`
