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$u_2=u_1.q=6\\⇒u_1=\dfrac{6}{q}\\S_3=\dfrac{u_1.(1-q^3)}{1-q}=\dfrac{6-6q^3}{q-q^2}=43\\$$⇔$\(\left[ \begin{array}{l}q=\dfrac{1}{6}\\q=6\end{array} \right.\)$\\•q=\dfrac{1}{6}\\⇒u_1=36\\S_6=\dfrac{36.\bigg[1-\bigg(\dfrac{1}{6}\bigg)^6\bigg]}{1-\dfrac{1}{6}}=\dfrac{9331}{216}\\•q=6\\⇒u_1=1\\S_6=\dfrac{1.(1-6^6)}{1-6}=9331$
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