Sagot :
Exercice 1
1) A=4x²-9-2x²-x+3=2x²-x-6
2) a) 4x² - 9 =(2x-3)(2x+3)
b) A=(2x+3)(x+4)
3) x=3/2 donne A=33 et x=-4 donne A=0
Exercice 3
1)A ) 5 ( 2x - 3 )² - ( 5x - 2 ) ( 5x + 2 )
=5(4x²-12x+9)-25x²+4
=-5x²-60x+49
B) 8 ( 2x - 1 ) ( 2x + 1 ) - 4 ( 3x - 1 ) ²
=8(4x²-1)-4(9x²-6x+1)
=-4x²+24x-12
2) C) ( 5x - 1 ) - 2 ( 5x - 1 ) ( x + 3 ) =(5x-1)(-2x-5)
D) 9x ² - 24x + 16 =(3x-4)²
E) 9 ( x - 1 ) ² - 16 ( x + 1 )² =(3x-3+4x+4)(3x-3-4x-4)=(7x+1)(-x-7)