Question

X y z
- = - = -
4 5 6
X+y+z=15
Det nr x,y,z

Answer 1

x / 4  = y / 5 = z / 6  = ( x + y + z )  / ( 4+ 5 + 6 ) = 15 / 15 = 1 
x / 4 = 1        x = 4 · 1 = 4 
y  / 5 = 1       y = 5· 1 = 5 
z  / 6 = 1       z = 6 · 1 = 6

Answer 2

  [tex]\frac{x}{4 }=\frac{y}{5}=\frac{z}{6}=\frac {x+y+z}{4+5+6}=\frac{15}{15}=1\\ x=4\,,\,y=5\,,\,z=6\,.[/tex]