Respuesta:
9.
[tex]2x - 15 + x + 10 + 2x - 30 = 180 \\ 5x - 35 = 180 \\ 5x = 180 + 35 \\ 5x = 215 \\ x = \frac{215}{5} \\ x = 43[/tex]
10.
[tex]x + 20 + 90 + 2x + 20 = 180 \\ 3x + 130 = 180 \\ 3x = 180 - 130 \\ 3x = 50 \\ x = \frac{50}{3} \\x = 16.6 [/tex]
