bonjour,
1)
(x+3) ( 2x+1 - 10x-12)=
(x+3) (-8x -11)
2)
(x-4) ( 2x+9 +21x +9) =
(x-4) ( 23x =18)
3)
(9x+6 ) = 3(3x+2)
(3x+2) ( 12x +3 +1-4x) =
(3x+2) ( 8x +4)
4)
(5x-10) = 5(x-2)
(x-2) ( 10x +15 - 15x -27) =
(x-2) ( -5x -12)
5)
9x² +6x +1 = (3x+1)²
(3x+1)( 3x+1 -4x+1)=
(3x+1) ( -x +2)
6)
(9x+18 ) = 9(x+2)
(4x+20) = 4(x+5)
9(x+2)² - 4(x+5)²
