[tex] > resolucao \\ \\ \geqslant progressao \: geometrica \\ \\ \geqslant \: a \: razao \: da \: pg \\ \\ \\ q = \frac{a2}{a1 } \\ \\ q = \frac{ - 40}{ - 20} \\ \\ q = 2 \\ \\ > > > > > > > > > > > > > > > > > > > > \\ \\ \\ q = \frac{a3}{a2} \\ \\ q = \frac{ - 80}{ - 40} \\ \\ q = 2 \\ \\ \\ \\ > < > < > < > < > < > < > < > < [/tex]