\(9.x=7.y\Rightarrow\frac{x}{7}=\frac{y}{9}\)

Áp dụng tính chất của dãy tỉ số bằng nhau ta có :

\(\frac{x}{7}=\frac{y}{9}=\frac{x+y}{7+9}=\frac{32}{16}=2\)

\(\Leftrightarrow\frac{x}{7}=2\Rightarrow x=14\)

\(\frac{y}{6}=2\Rightarrow y=12\)

Study well 

đây là toán lớp 7 các bạn nhé giải hhọ tôi nhé thanks

Ko cần chỉnh 😁

3x = 2y ; 7x = 5z

\(\Rightarrow\frac{x}{2}=\frac{y}{3};\frac{y}{5}=\frac{z}{7}\)

\(\Rightarrow\frac{x}{10}=\frac{y}{15};\frac{y}{15}=\frac{z}{21}\)

\(\Rightarrow\frac{x}{10}=\frac{y}{15}=\frac{z}{21}\)

Áp dụng tích chất của dãy tỉ số bằng nhau ta có :

\(\frac{x}{10}=\frac{y}{15}=\frac{z}{21}=\frac{x-y+z}{10-15+21}=\frac{32}{16}=2\)

\(\Rightarrow\frac{x}{10}=2\Rightarrow x=20\)

\(\frac{y}{15}=2\Rightarrow y=30\)

\(\frac{z}{21}=2\Rightarrow z=42\)

áp dụng dãy tí số bằng nhau ta có:

x/5 = y/-6 = z/7 = x+y-z/5+6-7 = 32/4 = 8

từ x/5=8 -> x=40

y/-6 =8 -> y= -48

z/7=8 -> z=56

Theo tính chất dãy tỉ số bằng nhau ta có:
\(\frac{x}{5}=\frac{y}{-6}=\frac{z}{7}=\frac{x+y-z}{5+\left(-6\right)-7}=\frac{32}{-8}=-4\)
\(\Rightarrow\hept{\begin{cases}x=-4.5=-20\\y=-4.\left(-6\right)=24\\z=-4.7=-28\end{cases}}\)

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\(\dfrac{x}{y}=\dfrac{9}{7}\)⇒\(\dfrac{x}{9}=\dfrac{y}{7}\)

\(\dfrac{y}{z}=\dfrac{7}{3}\)⇒\(\dfrac{y}{7}=\dfrac{z}{3}\)

⇒\(\dfrac{x}{9}=\dfrac{y}{7}=\dfrac{z}{3}\)

Áp dụng tính chất dãy tỉ số bằng nhau, ta có:

\(\dfrac{x}{9}=\dfrac{y}{7}=\dfrac{z}{3}=\dfrac{x-y+z}{9-7+3}=\dfrac{15}{5}=3\)

⇒\(\left\{{}\begin{matrix}x=3.9=27\\y=3.7=21\\z=3.3=9\end{matrix}\right.\)