2 √20- √50+3 √80- √320 √32- √50+ √98- √72 5 √ 3-3 √48+2 √75-1/3 √108

Đáp án+Giải thích các bước giải:

 `2\sqrt{20}-\sqrt{50}+3\sqrt{80}-\sqrt{320}`

`=2\sqrt{4.5}-\sqrt{25.2}+3\sqrt{16.5}-\sqrt{64.5}`

`=2.2.\sqrt{5}-5\sqrt{2}+3.4.\sqrt{5}-8\sqrt{5}`

`=4\sqrt{5}-5\sqrt{2}+12\sqrt{5}-8\sqrt{5}`

`=(4+12-8)\sqrt{5}-5\sqrt{2}`

`=8\sqrt{5}-5\sqrt{2}`

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`\sqrt{32}-\sqrt{50}+\sqrt{98}-\sqrt{72}`

`=\sqrt{16.2}-\sqrt{25.2}+\sqrt{49.2}-\sqrt{36.2}`

`=4\sqrt{2}-5\sqrt{2}+7\sqrt{2}-6\sqrt{2}`

`=(4-5+7-6)\sqrt{2}`

`=0`

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`5\sqrt{3}-3\sqrt{48}+2\sqrt{75}-1/3\sqrt{108}`

`=5\sqrt{3}-3\sqrt{16.3}+2\sqrt{25.3}-1/3\sqrt{36.3}`

`=5\sqrt{3}-3.4\sqrt{3}+2.5\sqrt{3}-1/3. 6\sqrt{3}`

`=5\sqrt{3}-12\sqrt{3}+10\sqrt{3}-2\sqrt{3}`

`=(5-12+10-2)\sqrt{3}`

`=\sqrt{3}`