Tìm x ( giải = tỉ lệ thức ) A x – 1 / x – 5 = 6/7 B x^2 / 6 = 24/25 15/07/2021 Bởi Genesis Tìm x ( giải = tỉ lệ thức ) A x – 1 / x – 5 = 6/7 B x^2 / 6 = 24/25
a) $\dfrac{x-1}{x-5}=\dfrac{6}{7}$ $↔7(x-1)=6(x-5)$ $↔7x-7=6x-30$ $↔7x-7-6x+30=0$ $↔x+23=0$ $↔x=23$ b) $\dfrac{x^2}{6}=\dfrac{24}{25}$ $↔x^2=\dfrac{24}{25}.6=\dfrac{144}{25}$ \(↔\left[ \begin{array}{l}x=\dfrac{12}{5}\\x=-\dfrac{12}{5}\end{array} \right.\) Bình luận
`a)(x – 1) / (x – 5) = 6/7` `=> ( x – 1) .7 = ( x – 5). 6` `=> 7x – 7 = 6x – 30` `=> 7x – 6x = ( – 30) + 7` `=> 1x = – 26` `=> x = – 26` `b)x^2 / 6 = 24/25` `=> x^2. 25 = 6.24` `=> x^2 .25 = 144` `=> x^2 = 144/25` `=> x =` \(\sqrt{\frac{144}{25}}\) `=> x = +-12/5` Bình luận
a) $\dfrac{x-1}{x-5}=\dfrac{6}{7}$
$↔7(x-1)=6(x-5)$
$↔7x-7=6x-30$
$↔7x-7-6x+30=0$
$↔x+23=0$
$↔x=23$
b) $\dfrac{x^2}{6}=\dfrac{24}{25}$
$↔x^2=\dfrac{24}{25}.6=\dfrac{144}{25}$
\(↔\left[ \begin{array}{l}x=\dfrac{12}{5}\\x=-\dfrac{12}{5}\end{array} \right.\)
`a)(x – 1) / (x – 5) = 6/7`
`=> ( x – 1) .7 = ( x – 5). 6`
`=> 7x – 7 = 6x – 30`
`=> 7x – 6x = ( – 30) + 7`
`=> 1x = – 26`
`=> x = – 26`
`b)x^2 / 6 = 24/25`
`=> x^2. 25 = 6.24`
`=> x^2 .25 = 144`
`=> x^2 = 144/25`
`=> x =` \(\sqrt{\frac{144}{25}}\)
`=> x = +-12/5`