Réponse :
Bonsoir;
Explications étape par étape
a) A = x² +2x +1+x² -6x +9 = 2x² -4x +10 = 2( x² - 2x +5)
B = 2x² +4x +34 = 2( x² +2x +17)
C = x² -8x +16 +4x² -49 = 5x² -8x -33
b ) A = 16x² +8x +1 -x² -6x -9 = 15x² + 2x -8
B = 4x² +12x +9 -x²+49 = 3x² +12x +58
C = x² -4 -x² +6x -9 = 6x - 3
D = x² -10x +25 -2x² +17x -35 = -x² + 7x -15
E = 3x² -5x -2 -4x² +12x -9 = -x² +7x -11