Question

пжжжжжжжж пожалуйста​

Answer 1

Ответ:

$b_{1} = -9\\ b_{2} = b_{1}*q = 3\\q = -\frac{1}{3} \\S_{5} = \frac{b_{1}*(q^{5}-1) }{q-1} = \frac{-9*(-\frac{1}{243}-1) }{-\frac{1}{3}-1} =\frac{-9*(\frac{-244}{243}) }{-\frac{4}{3} } =-\frac{244*3}{4*27} = -6\frac{7}{9}$