Question

b3=14,4 b6=388,8
b1=?

Answer 1

$b_3=14,4\; \; ;\; \; b_6=388,8\\\\b_3=b_1\cdot q^2\; \; \to \; \; b_1=\frac{b_3}{q^2}\\\\b_6=b_1\cdot q^5\; \; \to \; \; b_1=\frac{b_6}{q^5}\\\\\frac{b_3}{q^2}=\frac{b_6}{q^5}\; \; \to \; \; \frac{q^5}{q^2}=\frac{b_6}{b_3}\; \; \to \; \; q^3=\frac{388,8}{14,4}=27=3^3\; \; \Rightarrow \; \; q=3\\\\b_1=\frac{b_3}{q^2}=\frac{14,4}{9}=1,6$