Réponse :
bonjour
Explications étape par étape
1)A=(3x-1)²-25
9x²-6x+1-25
9x²-6x-24
B=(2x-1)²-(2x-1)(x+5)
4x²-4x+1-2x²-10x+x+5
2x²-13x+6
C=(5x-3)²-2(x-1)(5x-3)
25x²-30x+9-10x²+6x+10x-6
15x²-14x+3
2)A=(3x-1)²-25
(3x-1-5)(3x-1+5)
(3x-6)(3x+4)
3(x-2)(3x+4)
B=(2x-1)²-(2x-1)(x+5)
(2x-1)(+2x-1-x-5)
(2x-1)(x-6)
C=(5x-3)²-2(x-1)(5x-3)
(5x-3)(5x-3-2x+2)
(5x-3)(3x-1)
3)A=9x²-6x-24
=9*0²-6*0-24
=0-0-24
=-24
x=-2
=9*(-2)²-6*(-2)-24
=36+12-24
=24