Đáp án + giải thích các bước giải:
c) `\sqrt{4a}-2\sqrt{25a}-5\sqrt{4a}`
`=\sqrt{4}\sqrt{a}-2\sqrt{25}\sqrt{a}-5\sqrt{4}\sqrt{a}`
`=2\sqrt{a}-10\sqrt{a}-10\sqrt{a}`
`=-18\sqrt{a}`
d) `2\sqrt{3x}-\sqrt{48x}+\sqrt{108x}+\sqrt{3x}`
`=2\sqrt{3x}-\sqrt{16}\sqrt{3x}+\sqrt{36}\sqrt{3x}+\sqrt{3x}`
`=2\sqrt{3x}-4\sqrt{3x}+6\sqrt{3x}+\sqrt{3x}`
`=5\sqrt{3x}`
e) `(\sqrt{12}-2\sqrt{3}+5\sqrt{2}-3/4 \sqrt{48}) \sqrt{3}-\sqrt{24}`
`=(\sqrt{4}\sqrt{3}-2\sqrt{3}+5\sqrt{2}-3/4 \sqrt{16}\sqrt{3})\sqrt{3}-\sqrt{24}`
`=(2\sqrt{3}-2\sqrt{3}+5\sqrt{2}-3\sqrt{3})\sqrt{3}-\sqrt{24}`
`=(5\sqrt{2}-3\sqrt{3})\sqrt{3}-\sqrt{4}\sqrt{6}`
`=5\sqrt{6}-9-2\sqrt{6}`
`=3\sqrt{6}-9`
f) `\sqrt{16x+16}-\sqrt{9x+9}+\sqrt{25x+25} `
`=\sqrt{16}\sqrt{x+1}-\sqrt{9}\sqrt{x+1}+5\sqrt{x+1}`
`=4\sqrt{x+1}-3\sqrt{x+1}+5\sqrt{x+1}`
`=6\sqrt{x+1}`