a: \(\dfrac{-4}{8}=\dfrac{x}{-10}=\dfrac{-7}{y}=\dfrac{z}{-24}\)

=>\(\dfrac{x}{-10}=\dfrac{-7}{y}=\dfrac{z}{-24}=\dfrac{-1}{2}\)

=>\(\left\{{}\begin{matrix}x=\left(-10\right)\cdot\dfrac{\left(-1\right)}{2}=5\\y=\dfrac{-7\cdot2}{-1}=14\\z=\dfrac{-24\cdot\left(-1\right)}{2}=\dfrac{24}{2}=12\end{matrix}\right.\)

b: \(\dfrac{-3}{6}=\dfrac{x}{-2}=\dfrac{-18}{y}=\dfrac{-z}{24}\)

=>\(\dfrac{x}{-2}=\dfrac{-18}{y}=\dfrac{z}{-24}=\dfrac{-1}{2}\)

=>\(\dfrac{x}{2}=\dfrac{18}{y}=\dfrac{z}{24}=\dfrac{1}{2}\)

=>\(x=2\cdot\dfrac{1}{2}=1;y=18\cdot\dfrac{2}{1}=36;z=\dfrac{24}{2}=12\)

\(\frac{-3}{6}=\frac{x}{-2}=\frac{-18}{y}=\frac{-z}{24}\)

Ta có : 

\(\frac{x}{-2}=\frac{-3}{6}\Rightarrow x=\frac{-3.\left(-2\right)}{6}=1\)

\(\frac{-18}{y}=\frac{-3}{6}\Rightarrow y=\frac{-18.6}{-3}=36\)

\(\frac{-z}{24}=\frac{-3}{6}\Rightarrow\frac{-3.24}{6.-z}\Rightarrow z=\frac{-3.24}{-6}=12\)

\(\frac{x}{5}=\frac{y}{3}=\frac{z}{6}\Rightarrow\frac{3x}{15}=\frac{2y}{6}=\frac{2z}{12}\)

áp dụng tính chất dãy tỉ số bn ta có 

\(\frac{3x}{15}=\frac{2y}{6}=\frac{2z}{12}=\frac{3x-2y+2z}{15-6+12}=\frac{24}{21}=\frac{8}{7}\)

\(\Rightarrow\hept{\begin{cases}x=\frac{40}{7}\\y=\frac{24}{7}\\z=\frac{48}{7}\end{cases}}\)

đề bài câu a xem lại nhé 

b) \(\frac{x}{2}=\frac{y}{3}=\frac{z}{4};x+z=18\)

Áp dụng tính chất dãy tỉ số bằng nhau :

\(\frac{x}{2}=\frac{y}{3}=\frac{z}{4}=\frac{x+z}{2+4}=\frac{18}{6}=3\)

\(\Rightarrow\)\(x=3.2=6\)

\(y=3.3=9\)

\(z=3.4=12\)

ADTC dãy t/s bằng nhau ta có

\(\frac{x}{2}=\frac{y}{3}=\frac{z}{4}=\frac{x+z}{2+4}=\frac{18}{6}=3\)

\(\Rightarrow\hept{\begin{cases}x=6\\y=9\\z=12\end{cases}}\)

\(\Leftrightarrow\dfrac{x}{-2}=\dfrac{1}{-2}=\dfrac{-18}{y}=\dfrac{z}{-24}\)

=>x=1; y=36; z=12

x254n3jsm3,s3333

1)\(\dfrac{-3}{6}=\dfrac{x}{-2}=\dfrac{-18}{y}=\dfrac{-z}{24}\)

\(\Rightarrow x=-\dfrac{3}{6}\cdot\left(-2\right)=1\)

\(\Rightarrow y=-18:\dfrac{-3}{6}=36\)

\(\Rightarrow z=-\dfrac{3}{6}\cdot\left(-24\right)=12\)

câu cuối làm tương tự

1)\(\dfrac{-3}{6}=\dfrac{x}{-2}=\dfrac{-18}{y}=\dfrac{-z}{24}\)

\(\Rightarrow x=-\dfrac{3}{6}\cdot\left(-2\right)=1\)

\(\Rightarrow y=-18:\dfrac{-3}{6}=36\)

\(\Rightarrow z=-\dfrac{3}{6}\cdot\left(-24\right)=12\)

1)\(\dfrac{-3}{6}=\dfrac{x}{-2}=\dfrac{-18}{y}=\dfrac{-z}{24}\)

\(\Rightarrow x=-\dfrac{3}{6}\cdot\left(-2\right)=1\)

\(\Rightarrow y=-18:\dfrac{-3}{6}=36\)

\(\Rightarrow z=-\dfrac{3}{6}\cdot\left(-24\right)=12\)
2) \(\dfrac{x}{y}=\dfrac{2}{5}\Rightarrow\left\{{}\begin{matrix}x=2\\y=5\end{matrix}\right.\)

3) \(\dfrac{x}{-3}=\dfrac{4}{y}\Rightarrow\left\{{}\begin{matrix}x=4\\y=-3\end{matrix}\right.\)