Question

помогите срочно!!! да. 75 балов

Answer 1

$\displaystyle\bf\\1)\\\\b_{1}= \frac{2}{81} \\\\q=3\\\\b_{8} =b_{1} \cdot q^{7} =\frac{2}{81} \cdot3^{7}=\frac{2}{3^{4} } \cdot 3^{7} =2\cdot3^{3} =2\cdot 27=54\\\\\\2)\\\\b_{1} =14\\\\b_{4}=4,802 \\\\b_{4} =b_{1}\cdot q^{3} \\\\q^{3} =b_{4} :b_{1} =4,802:14=0,343\\\\q=\sqrt[3]{0,343} =0,7\\\\q=0,7$

$\displaystyle\bf\\3)\\\\b_{5} =-0,0648\\\\q=0,3\\\\b_{5} =b_{1} \cdot q^{4} \\\\b{1} =b_{5} :q^{4} =-0,0648:0,3^{4} =-0,0648:0,0081=-8\\\\b_{1} =-8$