Answer
$r=2;a_{1}=-3$
Work Step by Step
$\dfrac {a_{m}}{a_{n}}=r^{m-n}\Rightarrow \dfrac {a_{7}}{a_{2}}=r^{5}\Rightarrow \dfrac {-192}{-6}=r^{5}=32\Rightarrow r=2;a_{2}=a_{1}\times r\Rightarrow -6=a_{1}\times 2\Rightarrow a_{1}=-3$
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