bonjour
A = ( 2 x - 5 )² + ( 2 x - 5 ) ( 1 + 3 x ) + 4 x² - 25
1 ) A = 4 x² - 20 x + 25 + 2 x + 6 x² - 5 - 15 x + 4 x² - 25
A = 14 x² - 33 x - 5
2 ) A = ( 2 x - 5 ) ² + ( 2 x - 5 ) ( 1 + 3 x ) + ( 2 x - 5 ) ( 2 x + 5 )
A = ( 2 x - 5 ) ( 2 x - 5 + 1 + 3 x + 2 x + 5 )
A = ( 2 x - 5 ) ( 7 x + 1)