The 7th term of an AP is 4 and its common difference is - 4. What is its first term?

Given: a7 = 4


Common difference = d = - 4


To find: First term = a


Since, a7 = 4


⇒ a + 6d = 4


⇒ a + 6(-4) = 4


⇒ a = 4 + 24


⇒ a = 28

30