Question

The 8th term of an A.P is 5x the 3rd term while the seventh term is 9 greater than the 4th term write the 1st five term of the A-P​

Answer 1

`-(9)/(4)`

Explanation:

U₇ = U₄ + 9

U₄ + 3d = U₄ + 9

3d = 9

d = 3

U₈ = 5 × U₃

(U₁ + 7d) = 5(U₁ + 2d)

U₁ + 7d = 5U₁ + 10d

4U₁ = -3d

U₁ =
`-(3)/(4)d`

=
`-(3)/(4) *3`

=
`-(9)/(4)`