j: ĐKXĐ: \(x\ne9\)
\(\dfrac{3}{5}=\dfrac{-12}{9-x}\)
=>\(\dfrac{12}{x-9}=\dfrac{3}{5}\)
=>\(x-9=12\cdot\dfrac{5}{3}=20\)
=>x=20+9=29(nhận)
k: ĐKXĐ: \(x\ne-2\)
\(\dfrac{x+2}{3}=\dfrac{3}{x+2}\)
=>\(\left(x+2\right)^2=9\)
=>\(\left[{}\begin{matrix}x+2=3\\x+2=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\left(nhận\right)\\x=-5\left(nhận\right)\end{matrix}\right.\)
l: ĐKXĐ x<>4
\(\dfrac{x-4}{-5}=\dfrac{-5}{x-4}\)
=>\(\left(x-4\right)^2=\left(-5\right)\cdot\left(-5\right)=25\)
=>\(\left[{}\begin{matrix}x-4=5\\x-4=-5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=9\left(nhận\right)\\x=-1\left(nhận\right)\end{matrix}\right.\)
m: \(\dfrac{3}{4}=\dfrac{x}{x+1}\)(ĐKXĐ: x<>-1)
\(\Leftrightarrow4x=3\left(x+1\right)\)
=>4x=3x+3
=>4x-3x=3
=>x=3(nhận)
n: ĐKXĐ: x<>0
\(\dfrac{x+1}{2x}=\dfrac{2}{3}\)
=>\(2x\cdot2=3\left(x+1\right)\)
=>4x=3x+3
=>4x-3x=3
=>x=3(nhận)
o: ĐKXĐ: \(x\notin\left\{-1;-3\right\}\)
\(\dfrac{1}{x+1}=\dfrac{2}{x+3}\)
=>2(x+1)=x+3
=>2x+2=x+3
=>2x-x=3-2
=>x=1(nhận)
p: ĐKXĐ: \(x\notin\left\{5;\dfrac{1}{2}\right\}\)
\(\dfrac{5}{4x-2}=\dfrac{-1}{5-x}\)
=>\(\dfrac{5}{4x-2}=\dfrac{1}{x-5}\)
=>5(x-5)=4x-2
=>5x-25=4x-2
=>5x-4x=-2+25
=>x=23(nhận)
q: ĐKXĐ: x<>0
\(\dfrac{-30}{x}=\dfrac{6}{-13}\)
=>\(\dfrac{30}{x}=\dfrac{6}{13}\)
=>\(x=30\cdot\dfrac{13}{6}=5\cdot13=65\left(nhận\right)\)
r: \(\dfrac{2}{7}=\dfrac{x}{56}\)
=>\(x=56\cdot\dfrac{2}{7}=8\cdot2=16\)
