Question

Tìm x , y , z biết :

\(\dfrac{\left|x\right|}{11}=\dfrac{y}{12};7y=3z\) và \(2\left|x\right|-y+z=152\)

Answer 1

\(\dfrac{\left|x\right|}{11}=\dfrac{y}{12};7y=3z\)

\(\Rightarrow\dfrac{\left|x\right|}{11}=\dfrac{y}{12};\dfrac{y}{3}=\dfrac{z}{7}\)

\(\Rightarrow\dfrac{\left|x\right|}{11}=\dfrac{y}{12};\dfrac{y}{12}=\dfrac{z}{28}\)

\(\Rightarrow\dfrac{\left|x\right|}{11}=\dfrac{y}{12}=\dfrac{z}{28}\)

\(\Rightarrow\dfrac{2\left|x\right|}{22}=\dfrac{y}{12}=\dfrac{z}{28}\)

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

\(\dfrac{2\left|x\right|}{22}=\dfrac{y}{12}=\dfrac{z}{28}\)

\(=\dfrac{2\left|x\right|+y+z}{22+12+28}\)

\(=\dfrac{152}{62}=\dfrac{76}{31}\)

Áp dụng tính x;y;z