Zadanie 1
a_n=a_1*q^{n-1}
a_3=a_1*q^{3-1}
a_6=a_1*q^{6-1}
----------
12=a_1*q^2
96=a_1*q^5
-------
a_1=\frac{12}{q^2}
96=\frac{12}{q^2}*q^5
96=12*q^3
q^3=8
q=2
a_1=\frac{12}{q^2}
a_1=\frac{12}{4}=3 <–odpowiedź
albo
a_3*q^3=a_6
12*q^3=96|:12
q^3=8
q = 2
zadanie 2
a3 = −8 i a5 = −32
a_{n-1}*a_{n+1}={a_n}^2
{a_4}^2=-8 * (-32)
{a_4}^2=256
a_4=\sqrt{256}=16
-------
a_4=a_3*q
-8*q=16|:(-8)
q=-2