Question

8th term of an arithmetic sequence is 12 and 12th term is 8 then what is the 20th term​

Answer 1

Answer:

a+7d=12

a+11d=8

eliminating both the equation,

d=-1,a=19

a20=a+19d

19+19×-1=0

therefore the 20th term is 0

Step-by-step explanation:

Answer 2

Answer:

Step-by-step explanation:

so a + 7d = 12.............(1)

    a + 11d = 8.......(2)

subtract 1 from 2

4d = -4

d= -1

so, a + 7d = 12

a + 7x(-1) = 12

a -7 = 12

so, a= 5

so, a20 = 5 + (20 - 1)x -1

=5 - 19

= -14