Đáp án:
Câu 8: `-96`
Câu 9: `30`
Câu 10: `36`
Câu 11: `3\sqrt{2}-3`
Câu 12: `10-2\sqrt{15}+2\sqrt{10}`
Giải thích các bước giải:
Câu 8:
`(\sqrt{12}-\sqrt{48}-\sqrt{108}-\sqrt{192}).2\sqrt{3}`
`=(2\sqrt{3}-4\sqrt{3}-6\sqrt{3}-8\sqrt{3}).2\sqrt{3}`
`=-96`
Câu 9:
`(\sqrt{72}-2\sqrt{8}+\frac{1}{3}.\sqrt{18}).\sqrt{50}`
`=(6\sqrt{2}-4\sqrt{2}+\frac{1}{3} .3\sqrt{2}).5\sqrt{2}`
`=30`
Câu 10:
`3\sqrt{2}.(\sqrt{50}-2\sqrt{18}+\sqrt{98})`
`=3\sqrt{2}.(5\sqrt{2}-6\sqrt{2}+7\sqrt{2})`
`=3\sqrt{2}.6\sqrt{2}`
`=36`
Câu 11:
`3\sqrt{8}-\sqrt{50}-\sqrt{(2\sqrt{2}-3)^2}`
`=6\sqrt{2}-5\sqrt{2}-|2\sqrt{2}-3|`
`=\sqrt{2}-(3-2\sqrt{2})`
`=3\sqrt{2}-3`
Câu 12:
`(\sqrt{45}-\sqrt{12}-\sqrt{5}).\sqrt{5}+2\sqrt{10}`
`=(3\sqrt{5}-2\sqrt{3}-\sqrt{5}).\sqrt{5}+2\sqrt{10}`
`=(2\sqrt{5}-2\sqrt{3})\sqrt{5}+2\sqrt{10}`
`=10-2\sqrt{15}+2\sqrt{10}`
