t: ĐKXĐ: z<>0
\(\dfrac{42}{48}=\dfrac{-7}{z}\)
=>\(\dfrac{-7}{z}=\dfrac{7}{8}\)
=>\(z=-7\cdot\dfrac{8}{7}=-\dfrac{8}{1}=-8\)
u: ĐKXĐ: x<>0
\(\dfrac{-3+x}{x}=\dfrac{-2}{-1}\)
=>\(\dfrac{x-3}{x}=\dfrac{2}{1}\)
=>2x=x-3
=>2x-x=-3
=>x=-3(nhận)
t)\(\dfrac{42}{48}=\dfrac{-7}{x}\)
\(\Rightarrow\dfrac{-7}{x}=\dfrac{7}{8}\)
\(\Rightarrow x=\dfrac{-7\cdot8}{7}=-8\)
Vậy x = -8
u)\(\dfrac{-3+x}{x}=\dfrac{-2}{-1}\)
\(\Rightarrow\dfrac{-3+x}{x}=2\)
\(\Rightarrow-3+x=2x\)
\(\Rightarrow-3+x-2x=0\)
\(\Rightarrow-3+\left(x-2x\right)=0\)
\(\Rightarrow-3-x=0\)
\(\Rightarrow x=-3\)
Vậy x = -3
#Kễnh