Question

Bài 1: Tìm x

\(\dfrac{3}{x-5}\)=\(\dfrac{-4}{x+2}\)

Answer 1

$\frac{3}{{x - 5}} = \frac{{ - 4}}{{x + 2}}\left( {x \ne 5,x \ne - 2} \right)$
$\Leftrightarrow 3\left( {x + 2} \right) = - 4\left( {x - 5} \right)$
$\Leftrightarrow 3x + 6 = - 4x + 20$
$\Leftrightarrow 3x + 4x = 20 - 6$
$\Leftrightarrow 7x = 14$
$\Leftrightarrow x = \frac{{14}}{7} = 2\left( {TM} \right)$

Vậy $x=2$

Answer 2

\[\begin{align}

& \frac{3}{x-5}=\frac{-4}{x+2}\left( x\ne 5,x\ne -2 \right) \\

& \Leftrightarrow 3\left( x+2 \right)=-4\left( x-5 \right) \\

& \Leftrightarrow 3x+6=-4x+20 \\

& \Leftrightarrow 3x+4x=20-6 \\

& \Leftrightarrow 7x=14 \\

& \Leftrightarrow x=\frac{14}{7}=2\left( TM \right) \\

\end{align}\]