Question

\(\frac{x}{10}=\frac{y}{5};\frac{y}{2}=\frac{z}{3}\) và 2x-3y+4z=330

Answer 1

ta có:

\(\frac{x}{10}=\frac{y}{5}\Rightarrow\frac{x}{20}=\frac{y}{10}\)

\(\frac{y}{2}=\frac{z}{3}\Rightarrow\frac{y}{10}=\frac{z}{15}\)

\(\Rightarrow\frac{x}{20}=\frac{y}{10}=\frac{z}{15}\)

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

\(\frac{x}{20}=\frac{y}{10}=\frac{z}{15}=\frac{2x}{40}=\frac{3y}{30}=\frac{4z}{60}\)\(=\frac{2x-3y+4z}{40-30+60}\)\(=\frac{330}{70}=\frac{33}{7}\)

\(\Rightarrow\hept{\begin{cases}x=\frac{33}{7}.20=\frac{660}{7}\\y=\frac{33}{7}.10=\frac{330}{7}\\z=\frac{33}{7}.15=\frac{495}{7}\end{cases}}\)

Answer 2

x=660/7;y=330/7;c=495/7

Answer 3

x=660/7

y=330/7

z=495/7