a: ĐKXĐ: x<>0
\(\dfrac{2}{x}=\dfrac{8}{12}\)
=>\(x=\dfrac{2\cdot12}{8}\)
=>\(x=\dfrac{24}{8}=3\)
b: \(\dfrac{x}{5}=\dfrac{9}{-15}\)
=>\(\dfrac{x}{5}=\dfrac{-9}{15}=-\dfrac{3}{5}\)
=>x=-3
c: \(\dfrac{-7}{6}=\dfrac{x}{24}\)
=>\(x=-7\cdot\dfrac{24}{6}\)
=>\(x=-7\cdot4=-28\)
d: \(\dfrac{-11}{7}=\dfrac{33}{x}\)(ĐKXĐ: x<>0)
=>\(x=\dfrac{-33\cdot7}{11}=\dfrac{-33}{11}\cdot7=-3\cdot7=-21\)(nhận)
e: ĐKXĐ: x<>0
\(\dfrac{13}{18}=\dfrac{-39}{x}\)
=>\(x=-39\cdot\dfrac{18}{13}\)
=>\(x=-\dfrac{39}{13}\cdot18=-3\cdot18=-54\left(nhận\right)\)
f: \(\dfrac{x}{-7}=\dfrac{15}{-35}\)
=>\(\dfrac{x}{7}=\dfrac{15}{35}\)
=>\(\dfrac{x}{7}=\dfrac{3}{7}\)
=>x=3
g: ĐKXĐ: x<>0
\(-\dfrac{5}{x}=\dfrac{40}{64}\)
=>\(\dfrac{-5}{x}=\dfrac{5}{8}\)
=>\(x=\dfrac{-5\cdot8}{5}=-\dfrac{40}{5}=-8\)(nhận)
h: ĐKXĐ: x<>0
\(\dfrac{-32}{24}=\dfrac{4}{x}\)
=>\(\dfrac{4}{x}=\dfrac{-4}{3}\)
=>\(x=3\cdot\dfrac{4}{-4}=3\cdot\left(-1\right)=-3\)
