Question

In an Arithmetic progression, if a7= 16 and d= -2, find a9​

Answer 1

Answer:

• a₉ = 10

Step-by-step explanation:

Given:

• 7th term = a₇ = 16
• Common difference = d = -2

To find:

9th term = a₉ = ?

Solution:

We already know that:

aₙ = a + (n - 1)d

→ a₇ = a + (7 - 1) -2

→ 16 = a + 6 (-2)

→ 16 = a - 12

→ a = 16 + 12

→ a = 28

∴ The first term = 28

For finding the 9th term:

aₙ = a + (n - 1)d

➝ a₉ = a + (9 - 1)d

➝ a₉ = 28 + 8(-2)

➝ a₉ = 28 - 16

➝ a₉ = 12

∴ The 9th term of the A.P = a₉ = 12

Answer 2

Answer:

value of a9 is 12

Step-by-step explanation:

an=16 n=7 d=-2  a=?

an=a+(n-1)d

16=a+(7-1)-2

16=a-12

16+12=a

28=a

Therefore, a9=? n=9 a=28 d=-2

an=a+(n-1)d

an=28+(9-1)-2

an=28-16

an=12