Share
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
Question
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Answers ( )
`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)`