\(\frac{x}{2}=\frac{y}{3};\frac{y}{4}=\frac{z}{5}\Rightarrow\frac{x}{8}=\frac{y}{12};\frac{y}{12}=\frac{z}{15}\Rightarrow\frac{x}{8}=\frac{y}{12}=\frac{z}{15}\)
\(\text{Áp dụng tính chất của dãy tỉ số bằng nhau ta có:}\)
\(\frac{x}{8}=\frac{y}{12}=\frac{z}{15}=\frac{x+y+z}{8+12+15}=\frac{-35}{35}=-1\)
\(\text{Suy ra: }\frac{x}{8}=-1\Rightarrow x=-1.8=-8\)
\(\frac{y}{12}=-1\Rightarrow y=-1.12=-12\)
\(\frac{z}{15}=-1\Rightarrow z=-1.15=-15\)
Ta co : \(\frac{x}{2}=\frac{y}{3};\frac{y}{4}=\frac{z}{5}\) va x+y+z=-35
Ta lấy mau cua hai phan so cua \(\frac{y}{3}va\frac{y}{4}\) la 3 va 4
Lấy 3;4 thuộc BCNN
\(\Rightarrow BCNN\left(3;4\right)=12\)
\(\Rightarrow\frac{x}{2}=\frac{y}{3};\frac{y}{4}=\frac{z}{5}\Rightarrow\frac{x}{2}=\frac{4y}{12};\frac{3y}{12}=\frac{z}{5}\Rightarrow\frac{x}{8}=\frac{y}{12};\frac{y}{12}=\frac{z}{15}\Rightarrow\frac{x}{8}=\frac{y}{12}=\frac{z}{15}\)
\(\frac{x}{8}=\frac{y}{12}=\frac{z}{15}\) va x+y+z=-35
Áp dụng tính chất dãy tỉ số bằng nhau ta có :
\(\frac{x}{8}=\frac{y}{12}=\frac{z}{15}\Rightarrow\frac{x+y+z}{8+12+15}=-\frac{35}{35}=-1\)
Suy ra : \(\frac{x}{8}=-1\Rightarrow x=-1.8=-8\)
\(\frac{y}{12}=-1\Rightarrow y=-1.12=-12\)
\(\frac{z}{15}=-1\Rightarrow z=-1.15=-15\)
Vay : x=-8 ; y=-12 ; z=-15