Respuesta :

We have the following:

[tex]\begin{gathered} AC=AB+BC \\ AC=3x+3 \\ AB=-1+2x \\ BC=11 \end{gathered}[/tex]

replacing:

[tex]\begin{gathered} 3x+3=-1+2x+11 \\ 3x-2x=-1+11-3 \\ x=7 \end{gathered}[/tex]

the answer is what x is equal a 7