Question

tìm x,y,z biết 3x=2y;7y=5z va x-y+z=32

 

Answer 1

3x = 2y => \(\frac{x}{2}=\frac{y}{3}\)=> \(\frac{x}{10}=\frac{y}{15}\)

7y = 5z => \(\frac{y}{5}=\frac{z}{7}\)=> \(\frac{y}{15}=\frac{z}{21}\)

=> \(\frac{x}{10}=\frac{y}{15}=\frac{z}{21}=\frac{x-y+z}{10-15+21}=\frac{32}{16}=2\)

=> x = 2.10 = 20

y = 2.15 = 30

z = 2.21 = 42