\(\dfrac{a}{2}=\dfrac{b}{3}=\dfrac{c}{4}\)⇒\(\dfrac{a}{2}=\dfrac{2b}{6}=\dfrac{3c}{12}\)
Áp dụng tính chất dãy tỉ số bằng nhau, ta có:
\(\dfrac{a}{2}=\dfrac{2b}{6}=\dfrac{3c}{12}=\dfrac{a+2b-3c}{2+6-12}=\dfrac{-20}{-4}=5\)
⇒\(\left\{{}\begin{matrix}x=5.2=10\\y=5.3=15\\z=5.4=20\end{matrix}\right.\)
\(\dfrac{a}{2}=\dfrac{b}{3}=\dfrac{c}{4}\Rightarrow\dfrac{a}{2}=\dfrac{2b}{6}=\dfrac{3c}{12}\)
Áp dụng t/c của DS bằng nhau, ta có: \(\dfrac{a+2b-3c}{2+6-12}=\dfrac{-20}{-4}=5\)
\(\dfrac{a}{2}=5\Rightarrow a=10\)
\(\dfrac{b}{3}=5\Rightarrow b=15\)
\(\dfrac{c}{4}=5\Rightarrow c=20\)
tham khảo:
\(\dfrac{a}{2}=\dfrac{b}{3}=\dfrac{c}{4}=\dfrac{a+2b-3c}{2+2x3-3x4}=5\)
\(\Rightarrow\dfrac{a}{2}=5\Rightarrow a=5x2=10\)
\(\Rightarrow\dfrac{b}{3}=5\Rightarrow b=5x3=15\)
\(\Rightarrow\dfrac{c}{4}=5\Rightarrow c=20\)
