Answer:
[tex]\sf t_{20}= 0[/tex]
Step-by-step explanation:
Arithmetic sequence:
[tex]\sf \boxed{\bf n^{th} \ term = a + (n-1)d}\\\\\text{Here, a is the first term ; d is the common difference }[/tex]
6th term is 14 ⇒ [tex]\sf t_6 = 14[/tex]
a + (6 - 1)d = 14
a + 5d = 14 --------------(I)
14th term is 6 ⇒[tex]\sf t_{14} = 6[/tex]
a + (14-1)d = 6
a + 13d = 6 ----------------(II)
Subtract equation (II) from equation(I)
(I) a + 5d = 14
(II) a + 13d = 6
- - -
-8d = 8
d = 8 ÷(-8)
[tex]\sf \boxed{\bf d= (-1)}[/tex]
Plugin d = -1 in equation (I)
a + 5(-1) = 14
a -5 = 14
a = 14 + 5
[tex]\sf \boxed{\bf a = 19}[/tex]
20th term:
[tex]\sf t_{20}= 19 + 19*(-1)[/tex]
= 19 - 19
[tex]\sf \boxed{\bf t_{20} = 0}[/tex]
