Răspuns:
Explicație pas cu pas:
progresia geometrica: primul termen=b1 ratia=q
b2=b1·q bn=q^(n-1)
a) 3,9, 27, 81........b1=3 q=3
b4=b1·q³=3·3³=81
b6=b1·q^5=3· 3^5=3^6=(3³)²=27²= 729
b)6,18,27 b1=6 q=b2/b1=18/6=3
al treilea termen nu e 27 ,ci 18·3=54
b4=b3·q=54·3=162
b6=b4·q²=54·9=486