Question

TÌM X, Y, Z

  X:Y:Z =3:8:5 VÀ 3X +Y -2Z =14

Answer 1

Có:

\(\frac{x}{3}=\frac{y}{8}=\frac{z}{5}=\frac{3x}{9}=\frac{2z}{10}\)

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

\(\frac{x}{3}=\frac{y}{8}=\frac{z}{5}=\frac{3x}{9}=\frac{2z}{10}=\frac{3x+y-2z}{9+8-10}=\frac{14}{7}=2\)

\(\frac{x}{3}=2\Rightarrow x=6\)

\(\frac{y}{8}=2\Rightarrow y=16\)

\(\frac{z}{5}=2\Rightarrow z=10\)

Answer 2

\(\frac{x}{3}=\frac{y}{8}=\frac{z}{5}\Rightarrow\frac{3x}{9}=\frac{y}{8}=\frac{2z}{10}\Rightarrow\frac{3x+y-2z}{9+8-10}=\frac{14}{7}=2\)

\(\Rightarrow\frac{3x}{9}=2\Rightarrow3x=18\Rightarrow x=6\)

\(\Rightarrow\frac{y}{8}=2\Rightarrow y=16\)

\(\Rightarrow\frac{2z}{10}=2\Rightarrow2z=20\Rightarrow z=10\)

Answer 3

=>x/3=y/8=z/5va 3x+y-2z=14

Ap dung day ti so = nhau ,ta co:

  3x/9=y/8=2z/10=3x+y-2z/9+8-10=14/7=2

=>x/3=2=>x=6

    y/8=2=>y=16

    z/5=2=>z=10

Vay x=6;y=16;z=10

Chuc ban vao nam hoc gap nhieu may man nha!!