Đáp án:
Giải thích các bước giải:
`a) \sqrt{27}-3/2 \sqrt{12} +2\sqrt{75}`
`=\sqrt{3^2 . 3}-3/2 \sqrt{2^2 . 3} +2\sqrt{3.5^2}`
`=3\sqrt{ 3}-3/2 . 2\sqrt{ 3} +2.5\sqrt{3}`
`=3\sqrt{ 3}-3\sqrt{ 3} +10\sqrt{3}`
`=10\sqrt{3}`
`b)`
`P=(\sqrt{x}/(x-4) +1/(\sqrt{x}-2)):(2\sqrt{x})/(x-2\sqrt{x})`
`ĐK:x>0,x \ne 4`
`P=(\sqrt{x}/[(\sqrt{x}-2)(\sqrt{x}+2)] +(\sqrt{x}+2)/[(\sqrt{x}-2)(\sqrt{x}+2)]):(2\sqrt{x})/(\sqrt{x}(\sqrt{x}-2)`
`P=(2\sqrt{x}+2)/[(\sqrt{x}-2)(\sqrt{x}+2)]:(2)/(\sqrt{x}-2)`
`P=(2(\sqrt{x}+1))/[(\sqrt{x}-2)(\sqrt{x}+2)].(\sqrt{x}-2)/2`
`P=(\sqrt{x}+1)/(\sqrt{x}+2)`
`=>P-1=(\sqrt{x}+1)/(\sqrt{x}+2)-1`
`=>P-1=(-1)/(\sqrt{x}+2)`
Ta có `P-1=(-1)/(\sqrt{x}+2)`
`=>` Không có Min
