bonjour
16 x² + 48 x +36 = ( 4 x + 6 )²
64 - 25 x² = ( 8 - 5 x ) ( 8 + 5 x )
49 x² - 28 x + 4 = ( 7 x - 2 )²
9 x² - 25 + ( 3 x - 5 ) ( 2 x + 15 )
= ( 3 x - 5 ) ( 3 x + 5 ) + ( 3 x - 5 ) ( 2 x +15 )
= ' 3 x - 5 ) ( 3 x + 5 + 2 x + 15 )
= ( 3 x - 5 ) ( 5 x + 20 )
= 5 ( 3 x - 5 ) ( x + 4 )
