Bonjour je voudrais savoir cette question car j'ai un dm merci d'avance on considère l'expression a=(12x 3)(2x-7)-5x(2X-7)

Réponse :

Bonjour,

Développer

A = (12x + 3)(2x – 7) – 5x(2x – 7)

= 24x² – 84x + 6x – 21 – (10x² – 35x)

= 24x² – 84x + 6x – 21 – 10x² + 35x

= 24x² – 10x² – 84x + 6x + 35x – 21

= 14x² – 43x – 21

Factoriser

A = (12x + 3)(2x – 7) – 5x(2x – 7)

= (2x – 7)[(12x + 3) – 5x]

= (2x – 7)(12x + 3 – 5x]

= (2x – 7)(7x + 3)

bonjour

A =  24 x² - 84 x + 6 x - 21 -  10 x² + 35 x

A =   14 x² - 43 x - 21

A =  ( 2 x - 7 ) ( 12 x +3 - 5 x )

A = ( 2 x - 7 ) ( 7 x + 3 )