Answer:
The n th of the given sequence is
![t_(n) = 26-6 n](https://img.qammunity.org/2021/formulas/mathematics/middle-school/3316it46f0tw6sl98t5grkdiub6aoizt0e.png)
Explanation:
Step 1 :-
Given sequence is 20,14,8,2,.......this sequence in arithmetic progression but this sequence is decreasing sequence.
given first term is 20 and difference is
![d = second term- first term = 14-20=-6](https://img.qammunity.org/2021/formulas/mathematics/middle-school/yk3onh2gz2ar4m48b11bp1z2axka72rdvx.png)
now the nth term of given sequence is
by using formula
![t_(n)=a+(n-1)d](https://img.qammunity.org/2021/formulas/mathematics/middle-school/ex2bagl2cxczeirbby9751mungyx5gt9xn.png)
![t_(n)= 20+(n-1)(-6)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/e44ejfj6944s7wiknebljr9lksdroyddhj.png)
![t_(n)= 20-6 n+6](https://img.qammunity.org/2021/formulas/mathematics/middle-school/9g7ru8xdtp8nqia8pbuif5fo4z0zqwpkow.png)
final answer:-
![t_(n) = 26-6 n](https://img.qammunity.org/2021/formulas/mathematics/middle-school/3316it46f0tw6sl98t5grkdiub6aoizt0e.png)
verification:-
![t_(n) = 26-6 n](https://img.qammunity.org/2021/formulas/mathematics/middle-school/3316it46f0tw6sl98t5grkdiub6aoizt0e.png)
put n=1 we get first term is 20
put n=2 we get second term is 14
put n=3 we get third term is 8
put n=4 we get fourth term is 2
so the n th term of sequence is
![t_(n) = 26-6 n](https://img.qammunity.org/2021/formulas/mathematics/middle-school/3316it46f0tw6sl98t5grkdiub6aoizt0e.png)