Răspuns :
= [ ( x² + 2x ) ² + 2(x²+2x ) + 4 ( x²+2x ) + 8] +1 =
= [ ( x² +2x )² + 6( x² +2x) + 8 + 1 - 1] +1 =
= [ ( x² +2x )² + 6( x² +2x) + 9 - 1] +1 =
= [ ( x² +2x )² + 6( x² +2x) + 3² - 1] +1 =
= ( x² + 2x +3)² -1 +1 = ( x² +2x +3 )²
= [ ( x² +2x )² + 6( x² +2x) + 8 + 1 - 1] +1 =
= [ ( x² +2x )² + 6( x² +2x) + 9 - 1] +1 =
= [ ( x² +2x )² + 6( x² +2x) + 3² - 1] +1 =
= ( x² + 2x +3)² -1 +1 = ( x² +2x +3 )²