Answer:
; {-3,-9, -27,- 81, -243, ...}
; {-3, 9,-27, 81, -243, ...}
; {3, 1.5, 0.75, 0.375, 0.1875, ...}
; {243, 81, 27, 9, 3, ...}
Explanation:
The first explicit equation is
![a_n=-3(3)^(n-1)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/gi3pgqgiusid3ug1anyfca2u4blunpavb1.png)
At n=1,
![a_1=-3(3)^(1-1)=-3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/da33bofbqvv36gehrl1s1tx11a12m8m8vo.png)
At n=2,
![a_2=-3(3)^(2-1)=-9](https://img.qammunity.org/2020/formulas/mathematics/middle-school/93fcchrebgiq8e8inu8di6ovrvrbcsfkcw.png)
At n=3,
![a_3=-3(3)^(3-1)=-27](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ml7ute3bnuzpsni6z0mbuidpykho6y46k1.png)
Therefore, the geometric sequence is {-3,-9, -27,- 81, -243, ...}.
The second explicit equation is
![a_n=-3(-3)^(n-1)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/qv4ffrnr12apthuj00igifz1ks7htsmwnh.png)
At n=1,
![a_1=-3(-3)^(1-1)=-3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/780k4fq21zwg9zsn955d1wz85sxidpk1k7.png)
At n=2,
![a_2=-3(-3)^(2-1)=9](https://img.qammunity.org/2020/formulas/mathematics/middle-school/9l4bd99rwlahtf9sgq2mbn6sj7sf606yp0.png)
At n=3,
![a_3=-3(-3)^(3-1)=-27](https://img.qammunity.org/2020/formulas/mathematics/middle-school/csd5os4c3maebvx3hs41ufzcy4shz7ku5g.png)
Therefore, the geometric sequence is {-3, 9,-27, 81, -243, ...}.
The third explicit equation is
![a_n=3((1)/(2))^(n-1)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ieh6puhzv1vubuh1ucwkacln85oxeo6sqx.png)
At n=1,
![a_1=3((1)/(2))^(1-1)=3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/9har2ya0hpkye46imct7q4lclkwtyoo1kt.png)
At n=2,
![a_2=3((1)/(2))^(2-1)=1.5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/epfxdvzai4n12m3cchgx7vg2pp09geisxt.png)
At n=3,
![a_3=3((1)/(2))^(3-1)=0.75](https://img.qammunity.org/2020/formulas/mathematics/middle-school/y367dv7gxxnhzc4oaso3tmnil4fkfhbzxw.png)
Therefore, the geometric sequence is {3, 1.5, 0.75, 0.375, 0.1875, ...}.
The fourth explicit equation is
![a_n=243((1)/(3))^(n-1)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/10sdjnrv2boot8lqw1gyxupy8c2it2rrjf.png)
At n=1,
![a_1=243((1)/(3))^(1-1)=243](https://img.qammunity.org/2020/formulas/mathematics/middle-school/vt3aknfurcvtil1ffvg6c6yw69mf70bz24.png)
At n=2,
![a_2=243((1)/(3))^(2-1)=81](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ohddvem8pmp7vjezbnmj4q75gw989370td.png)
At n=3,
![a_3=243((1)/(3))^(3-1)=27](https://img.qammunity.org/2020/formulas/mathematics/middle-school/1vitzodvj5rdb39bqjmplexs6p8k0rva7i.png)
Therefore, the geometric sequence is {243, 81, 27, 9, 3, ...}.