Respuesta :

let's say Artaud's age is "x", its opposite will then be -x, so

[tex]\bf \stackrel{\textit{opposite of his age plus 40}}{-x+40}~~\stackrel{is}{=}~~28\implies -x+40-28=0 \\\\\\ -x+12=0\implies \boxed{12=x}[/tex]

Answer:

12 years old

Step-by-step explanation:

28 - 40 = -12

Note that -12 is the opposite of 12.

Artaud is 12