Question

Найдите сумму 7 первых членов геометрической прогрессии
-12,-24,-48,,,,,

Answer 1

-96,-192,-384,-768,-1536,-3072,-6344

Answer 2

q=b2/b1=-24/-12=2

b1•(q^7–1) -12•127
S7 = --------------- = ----------- = –1524
q–1 1