Respuesta :

gmany

[tex]|3x|=9\iff3x=9\ \vee\ 3x=-9\qquad\text{divide both sides by 3}\\\\x=3\ \vee\ x=-3[/tex]

  • |3x|=9 means that 3x=-9 or 3x=9 so x=3 and x=-3