Question

Find the next two numbers in the sequence 5,2,-1,…

Answer 1

The answer is (-4) and (-7).

Explanation:

Given;

• a₁ = 5
• a₂ = 2
• a₃ = (-1)

To Find;

• a₄ = ?
• a₅ = ?

Formula;

• aₙ = a + (n – 1) × d

Now, for common difference (d)

d = a₂ – a₁ = 2 – 5 = -3

d = a₃ – a₂ = (-1) – 2 = -3

Here, common difference is same everywhere.

So, for fourth term or n = 4

aₙ = a + (n – 1) × d

a₄ = 5 + (4 – 1) × (-3)

a₄ = 5 + 3 × (-3)

a₄ = 5 – 9

a₄ = -4

Then, for fifth term or n = 5

a₅ = 5 + (5 – 1) × (-3)

a₅ = 5 + 4 × (-3)

a₅ = 5 – 12

a₅ = -7

Thus, The fourth term is (-4) and fifth term is (-7).