Réponse:
Exercice 2 :
a) -2x +5 -4x +3
= -2x -4x +5 +3
= -6x + 8
b) -5x +4x +3
= -x +3
c) x² +x +3x +5x² +1
= x² +5x² +x +3x +1
= 6x² +4x +1
d) 6x² -3 +5x -7x² +4 -2x
= 6x² -7x² +5x -2x -3 +4
= -x² +3x +1
e) -2x × 3x +2x +3x² -4x
= -6x² +3x² +2x -4x
= -3x² -2x
f) 2×(3x²) - (4x)×x +x²
= 6x² - 4x² + x²
= 2x² +x²
= 3x²
Exercice 3 :
a) 3x +5x × (-2x) + x×2
= 3x -10x² + 2x
= 3x +2x -10x²
= 5x -10x²
b) 2+ 3×4 -x -x
= 2+ 12 -2x
= 14 -2x
c) (-x) × (-x) + (-x)×x
= x² + -x²
= x² -x²
= 0
d) -3×2 + (x×5) × 3 + x×2x
= -6 + 5x ×3 + 2x²
= -6 + 15x + 2x²
