Question

геометрические прогресия ​

Answer 1

$left { {{b_{6}=5} atop {b_{3}=40}} right.\\:left { {{b_{1} *q^{5}=5 } atop {b_{1}*q^{2}=40}} right.\ ------\q^{3}=frac{1}{8}\\q=frac{1}{2}\\b_{n} =b_{1}*q^{n-1}\\b_{n}=b_{n-1}*q\\b_{7} =b_{6}*q=5*frac{1}{2}=2,5$