Lê Quốc Trần Anh Coordinator
10/06/2018 at 06:31-
Alone 14/06/2018 at 01:07
\(\dfrac{x}{8}=\dfrac{y}{3}=\dfrac{z}{10}\Rightarrow\dfrac{x^2}{64}=\dfrac{xy}{24}=\dfrac{yz}{30}=\dfrac{zx}{80}=\dfrac{xy+yz+zx}{24+30+80}=\dfrac{1206}{134}=9\)
\(\Rightarrow x^2=64.9=8^2.3^2\Rightarrow x=\pm24\)
With x=24 then y=24:8.3=9;z=30
With x=-24 then y=-9;z=-30
Lê Quốc Trần Anh selected this answer. -
Nguyễn Mạnh Hùng 15/06/2018 at 01:35
We have:
\(\dfrac{x}{8}=\dfrac{y}{3}=\dfrac{z}{10}\)
\(\Rightarrow\dfrac{x^2}{64}=\dfrac{xy}{24}=\dfrac{yz}{30}=\dfrac{xz}{80}\)
Apply the same sequence properties, we have:
\(\dfrac{x^2}{64}=\dfrac{xy}{24}=\dfrac{yz}{30}=\dfrac{xz}{80}=\dfrac{xy+yz+xz}{24+30+80}=\dfrac{1206}{134}=9\)
So \(x^2=9.64=576\)\(\Rightarrow x=24\)
\(\dfrac{xy}{24}=9\Rightarrow xy=24.9=216\Rightarrow y=9\)
\(\dfrac{yz}{30}=9\Rightarrow yz=270\Rightarrow z=30\)
So \(\left(x;y;z\right)=\left(24;9;30\right)\)