So, missing term = 112 x 5 + 5 = 565.

So, missing term = 72 + 44 = 116.

Thus, the sequence 20, 20, 19, 16, 17, 13, 14, 11, xv x2 is a combination of two series :

I. 20, 19, 17, 14, x₁ and II. 20, 16, 13, 11, x₂

The pattern in I is - 1, - 2, - 3,......So, missing term, x₁ = 14 - 4 = 10.

The pattern in II is - 4, - 3, - 2,......So, missing term, x₂ = 11 - 1 = 10.

So, missing term = 210 + [6 x (6 + 15)] = 210 + 126 = 336.

I. 625, 125, 25, 5 and II. 5, 25, ?

The pattern in I is ÷ 5, while that in II is x 5. So, missing term = 25 x 5 = 125.

So, missing term = 310 + 120 = 430.

So, missing term = 10 x 10 + 1 = 101.

So, missing term = 427 + (5 x 16²) = 427 + 1280 = 1707.

So, missing term = 24 x 5 = 120.

Thus, the sequence 2, 15, 4, 12, 6, 7, x₁ x₂ is a combination of two series :

I. 2, 4, 6, x₁ and II. 15, 12, 7, x₂I consists of consecutive even numbers.

So, missing term, x₁ = 8.

The pattern in II is - 3, - 5,......So, missing term, x₂ = 7 - 7 = 0.