Question

Tìm 3 số x, y, z ,biết rằng:

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

Answer 1

x/2=y/3=>x/8=y/12

y/4=z/5=>y/12=z/15

=>x/8=y/12=z/15=(x+y-z)/(8+12-15)=10/5=2(áp dụng tính chất dãy tỉ số = nhau;x+y-z=10)

=>x/8=2=>x=16

y/12=2=>y=24

z/15=2=>z=30

Answer 2

\(\frac{x}{2}=\frac{y}{3}\Rightarrow\frac{x}{8}=\frac{y}{12}\)

\(\frac{y}{4}=\frac{z}{5}\Rightarrow\frac{y}{12}=\frac{z}{15}\)

\(\Rightarrow\frac{x}{8}=\frac{y}{12}=\frac{z}{15}=\frac{x+y-x}{8+12-15}=2\)

Ta có \(\frac{x}{8}=2\Rightarrow x=16\)

\(\frac{y}{12}=2\Rightarrow y=24\)

\(\frac{z}{15}=2\Rightarrow z=30\)

Vậy x=16; y=24; z=30