1 - x2	=	9
	x		20

     20 - 20x² = 9x

     20x² + 9x - 20 = 0

     20x² + 25x - 16x - 20 = 0

     5x(4x + 5) - 4(4x + 5) = 0

     (4x + 5)(5x - 4) = 0

Formula: (Divisor*Quotient) + Remainder = Dividend.

Soln:

(56*Q)+29 = D -------(1)

D%8 = R -------------(2)

From equation(2),

((56*Q)+29)%8 = R.

=> Assume Q = 1.

=> (56+29)%8 = R.

=> 85%8 = R

=> 5 = R.

(xⁿ + 1) will be divisible by (x + 1) only when n is odd.

(67⁶⁷ + 1) will be divisible by (67 + 1)

(67⁶⁷ + 1) + 66, when divided by 68 will give 66 as remainder.

(6n² + 6n) = 6n(n + 1), which is always divisible by 6 and 12 both, since n(n + 1) is always even.