\(\dfrac{3-x}{x+12}=\dfrac{3}{5}\left(đk:x\ne-12\right)\)
\(\Rightarrow3\left(x+12\right)=5\left(3-x\right)\)
\(\Rightarrow3x+36=15-5x\)
\(\Rightarrow8x=-21\Rightarrow x=-\dfrac{21}{8}\left(tm\right)\)
a) \(\dfrac{3-x}{x+12}=\dfrac{3}{5}\)
\(\Rightarrow5\left(3-x\right)=3\left(x+12\right)\)
\(\Rightarrow15-5x=3x+36\)
\(\Rightarrow15-5x-36=3x\)
\(\Rightarrow-21-5x=3x\)
\(\Rightarrow-21=8x\)
\(\Rightarrow x=\dfrac{-21}{8}\)
\(\dfrac{3-x}{x+12}=\dfrac{3}{5}\left(ĐK:x\ge-12\right)\)
<=> 5(3 - x) = 3(x + 12)
<=> 15 - 5x = 3x + 36
<=> 15 - 36 = 3x + 5x
<=> 8x = -21
<=> \(x=\dfrac{-21}{8}\left(TM\right)\)
