x 4 2 x 3 + 3 x 2 2 x + 1 x 4 + x + 1 x + x 1 x 2 + 2 x + 1 2 x 3 + 2 x 2 + x + x 3 2 4 x 2 x 4 + 1 2 x 2 + 1 =

= ( x 2 x + 1 ) 2 x ( x + 1 ) ( x 2 x + 1 ) + 1 x + x 1 ( x + 1 ) 2 2 x ( x + 1 ) 2 + x 3 2 4 x 2 x 4 + 1 2 x 2 + 1 =

= x 2 x + 1 x ( x + 1 ) + 1 x + x 1 ( x + 1 ) 2 2 x ( x + 1 ) 2 + x 3 2 4 x 2 x 4 + 1 2 x 2 + 1 =

= 4 x ( x + 1 ) ( x 2 x + 1 ) + 4 x ( x + 1 ) 2 + 4 x 2 ( x 1 ) 8 x + ( x + 1 ) 2 ( x 3 2 ) x 3 ( x + 1 ) 2 + 2 ( x + 1 ) 2 + 4 x 2 ( x + 1 ) 2 4 x 2 ( x + 1 ) 2 =

= 4 x ( x 3 + 1 + x 2 x 2 ) + ( x + 1 ) 2 ( 4 x + x 3 2 x 3 + 2 + 4 x 2 ) 4 x 2 ( x + 1 ) 2 =

= 4 x ( x 3 + x 2 x 1 ) + ( x + 1 ) 2 ( 4 x 2 + 4 x ) 4 x 2 ( x + 1 ) 2 =

= x 3 + x 2 x 1 + ( x 2 + 2 x + 1 ) ( x + 1 ) x ( x + 1 ) 2 =

= x 3 + x 2 x 1 + x 3 + x 2 + 2 x 2 + 2 x + x + 1 x ( x + 1 ) 2 =

= 2 x 3 + 4 x 2 + 2 x x ( x + 1 ) 2 =

= 2 x ( x 2 + 2 x + 1 ) x ( x + 1 ) 2 = 2