Cho P=(1/√x-1+1/x-1):(2-√x-4/√x-1) a, tìm đkxđ. b, rút gọn P. c, tìm x để P=1/4 20/07/2021 Bởi Alice Cho P=(1/√x-1+1/x-1):(2-√x-4/√x-1) a, tìm đkxđ. b, rút gọn P. c, tìm x để P=1/4
`P=(1/(\sqrt{x}-1)+1/(x-1)):(2-(\sqrt{x}4)/(\sqrt{x}-1))` ĐKXD: `x≥0,x\ne1;4` `P=(1/(\sqrt{x}-1)+1/(x-1)):(2-(\sqrt{x}-4)/(\sqrt{x}-1))` `=(\sqrt{x}+1+1)/(x-1):(2\sqrt{x}-2-\sqrt{x}+4)/(\sqrt{x}-1)` `=(\sqrt{x}+2)/(x-1):(\sqrt{x}+2)/(\sqrt{x}-1)` `=(\sqrt{x}+2)/((\sqrt{x}-1)(\sqrt{x}+1)) . (\sqrt{x}-1)/(\sqrt{x}+2)` `=1/(\sqrt{x}+1)` `P=1/4` `⇔1/(\sqrt{x}+1)=1/4` `⇔\sqrt{x}+1=4` `⇔\sqrt{x}=3` `⇔x=9(TM)` Bình luận
`P=(1/(\sqrt{x}-1)+1/(x-1)):(2-(\sqrt{x}4)/(\sqrt{x}-1))`
ĐKXD: `x≥0,x\ne1;4`
`P=(1/(\sqrt{x}-1)+1/(x-1)):(2-(\sqrt{x}-4)/(\sqrt{x}-1))`
`=(\sqrt{x}+1+1)/(x-1):(2\sqrt{x}-2-\sqrt{x}+4)/(\sqrt{x}-1)`
`=(\sqrt{x}+2)/(x-1):(\sqrt{x}+2)/(\sqrt{x}-1)`
`=(\sqrt{x}+2)/((\sqrt{x}-1)(\sqrt{x}+1)) . (\sqrt{x}-1)/(\sqrt{x}+2)`
`=1/(\sqrt{x}+1)`
`P=1/4`
`⇔1/(\sqrt{x}+1)=1/4`
`⇔\sqrt{x}+1=4`
`⇔\sqrt{x}=3`
`⇔x=9(TM)`