Đáp án+Giải thích các bước giải:
`a)`
`A=\sqrt{75}+\sqrt{48}-\sqrt{300}`
`=\sqrt{25.3}+\sqrt{16.3}-\sqrt{100.3}`
`=5\sqrt{3}+4\sqrt{3}-10\sqrt{3}`
`=(5+4-10).\sqrt{3}`
`=-\sqrt{3}`
`b)`
`B=\sqrt{98}-\sqrt{72}+0,5\sqrt{8}`
`=\sqrt{49.2}-\sqrt{36.2}+0,5.\sqrt{4.2}`
`=7\sqrt{2}-6\sqrt{2}+0,5.2\sqrt{2}`
`=7\sqrt{2}-6\sqrt{2}+\sqrt{2}`
`=(7-6+1).\sqrt{2}`
`=2\sqrt{2}`
`c)`
`C=(2\sqrt{3}+\sqrt{5}).\sqrt{3}-\sqrt{60}`
`=2\sqrt{3}.\sqrt{3}+\sqrt{5}.\sqrt{3}-\sqrt{4.15}`
`=2.3+\sqrt{15}-2\sqrt{15}`
`=6-\sqrt{15}`
