Respuesta :

[tex]\begin{gathered} C=x+12 \\ Then \\ (x+12)+(2x+9)+(3x-1)=180 \\ 6x+20=180 \\ 6x=180-20 \\ 6x=160 \\ x=\frac{160}{6} \\ x=26.7 \\ C=26.7+12 \\ C=38.7 \\ \text{The value of C is 38.7} \end{gathered}[/tex]