Question

The 7th term of an AP is -4 and it's 13th term is -16 . Find the A.P

Answer 1

★ Answer

• 7th term of AP = -4
• 13th term of AP = -16

Let the First term of AP be a and Common difference be d.

As We know that How to find the any number of term of an AP using Tⁿ = a + (n-1)d as:

So, 7th term will be,

→ Tⁿ = a + (n-1)d

→ -4 = a + (7-1)d

→ -4 = a + 6d [1]

Again, 13th term will be,

→ -16 = a + (13-1)d

→ -16 = a + 12d [2]

After Calculating [1] and [2] Equation, we've got that d = -2.

→ -4 = a + 6d

→ -4 = a + 6 × (-2)

→ -4 = a -12

→ -4 +12 = a

→ a = 8

Hence, The AP will be 8,6,4... .