Ta có: `x/2 = y/3 ; y/4 = z/5 -> x/8 = y/12 ; y/12 = z/15 -> x/8 = y/12 = z/15`
Áp dụng tính chất dãy tỉ số bằng nhau ta có:
`x/8 = y/12 = z/15 =`\(\dfrac{x+y+z}{8+12+15}=\dfrac{5}{35}=\dfrac{1}{7}\)
`=>`\(\left\{{}\begin{matrix}\dfrac{x}{8}=\dfrac{1}{7}\\\dfrac{y}{12}=\dfrac{1}{7}\\\dfrac{z}{15}=\dfrac{1}{7}\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=\dfrac{1}{7}\cdot8=\dfrac{8}{7}\\y=\dfrac{1}{7}\cdot12=\dfrac{12}{7}\\z=\dfrac{1}{7}\cdot15=\dfrac{15}{7}\end{matrix}\right.\)
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