Respuesta :

llefevre
x+2x=18
3x=18
x=6

2(6)=12

hope this helps
gmany
[tex]n\ \text{-first number}\\2n\ \text{second number}\\\\n+2n=18\\3n=18\ \ \ |:3\\n=6\to2n=2\cdot6=12[/tex]
Answer: 6 and 12.