Respuesta :

6 + x ≤ 18

isolate the x, subtract 6 from both sides

x + 6 (-6) ≤ 18 (-6)

x ≤ 18 (-6)

x ≤ 12

x ≤ 12 is your answer

hope this helps
Written in numerical form, it would look a bit like this: 

6 + x ≤ 18 

≤ means 'equal to or less than'