Sagot :
(3x-7)² - 3(3x-6)(x+2)
= 9x² - 42x + 49 - 3(3x² + 6x - 6x - 12)
= 9x² - 42x + 49 - 9x² - 36
= 42x - 13
(x-1)² - 3(x-1)
= (x-1)(x-1-3)
= (x-1)(x-4)
= 9x² - 42x + 49 - 3(3x² + 6x - 6x - 12)
= 9x² - 42x + 49 - 9x² - 36
= 42x - 13
(x-1)² - 3(x-1)
= (x-1)(x-1-3)
= (x-1)(x-4)
Exercice 2 :
Développer et réduire C :
C = (3x - 7)² - 3 (3x - 6) (x + 2)
C = 9x² - 42x + 49 - 3 (3x² + 6x - 6x - 12)
C = 9x² - 42x + 49 - 9x² - 36
C = 42x - 13
Exercice 3 :
Factoriser E :
E = (x - 1)² - 3 (x - 1)
E = (x - 1) (x - 1 - 3)
E = (x - 1) (x - 4)
Développer et réduire C :
C = (3x - 7)² - 3 (3x - 6) (x + 2)
C = 9x² - 42x + 49 - 3 (3x² + 6x - 6x - 12)
C = 9x² - 42x + 49 - 9x² - 36
C = 42x - 13
Exercice 3 :
Factoriser E :
E = (x - 1)² - 3 (x - 1)
E = (x - 1) (x - 1 - 3)
E = (x - 1) (x - 4)