Respuesta :

we have

[tex]\begin{gathered} (3x+6)+(6x+3)=180 \\ 3x+6+6x+3=180 \\ 9x+9=180 \\ 9x+9-9=180-9 \\ 9x=171 \\ \frac{9x}{9}=\frac{171}{9} \\ x=19 \end{gathered}[/tex]

answer: B. 19

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