Question

for an A.P. t17=54 and t9=30 then find the first term a and common difference d​

Answer 1

Answer:

a = 6

d = 3

Step-by-step explanation:

t 17 = 54

t 17 = a + (n-1) d

54 = a+(17-1)d

54 = a + 16d..(1)

t9 = 30

t9= a + (n-1) d

30 = a+(9-1)d

30=a+8d..(2)

1 - 2

8d = 24

d = 24/8

d = 3

put d = 3 in (2)

30 = a + 8(3)

30 - 24 = a

a = 6