выразите z через x x =2 7/9y y=0,81z

x=2 7/9 y
x=25/9y
y=x:25/9
y=9/25x
y=0.81z

9/25x=0.81z
z=9/25x:0.81
z=9/25x:81/100
z=9/25*100/81 x
[tex]z= \frac{9*100}{81*25}x = \frac{4}{9} x[/tex]