Bonsoir,

Paris:

4x² +12x +9 + 14x² -4x +21x -6

=  18x² +29x +3

(2x+3) ( 2x+3 +7x-2)

= (2x+3) (9x +1)

4 *(-4)² +12*-4 +9 + 14*(-4)²  -4x*-4+21*-4 -6

=4*16 - 48 +14 * 16 +16 -84 -6

= 64 -48+224 +16-84-6

= 166

Antilles:

16 -( 4x² +12x +9)

= 16 -4x² -12x -9

= -4x² -12x +16 -9

= -4x² -12x + 7

x=-1

16 -4(1)  -12*-1 -9

= 16-4 +12 -9

= 15

(4-2x-3) ( 4 +2x+3)

identité remarquable

(-2x +1) ( 2x +7 )