Sagot :
Exercice 1.
= -15x +12
= 8x² - 14x - 32x + 56
= 8x² - 46x + 56
= x - (5x² - 3x + 35x - 21)
= x - 5x² -32x + 21
= -5x² - 31x + 21
Exercice 2.
= 10x - 35
= 12x - 4
= 4 - 3x + 15
= -3x + 19
= 5x + 10x - 5
= 15x - 5
= 6x + 10 - 4x - 8
= 2x - 2
Exercice 3.
= x² + 4x + 3x + 12
= x² + 7x + 12
= -2x² + 4x + 3x - 6
= -2x² + 7x - 6
= -8x² - 4x + 6x + 3
= -8x² + 2x + 3
= 35x² - 28x - 10x + 8
= 35x² - 38x + 8
= -24x² + 21x - 32x + 28
= -24x² - 11x + 28
Exercice 4.
= 5 + (8x - 6x² - 28 + 21x)
= 5 - 6x² + 29x - 28
= -6x² + 29x - 23
= 3 - ( -4x² + 8x - x + 2)
= 3 + 4x² - 7x - 2
= 4x² - 7x + 1
= 5x - 1 + (6x² + 2x - 9x - 3)
= 5x - 1 + 6x² - 7x - 3
= 6x² - 2x - 4
= 4x² - ( -5x² + 15x + 2x - 6)
= 4x² + 5x² - 17x + 6
= 9x² - 17x + 6
= 2x² + 10x - 3x - 15 - 8x + 4
= 2x² - x - 11