Réponse :
Explications étape par étape :
Bonjour
Factorisons l'expression 64-25x²-(8-5x)².
= (8² - -5x)² - (8 - 5x)²
= (8 - 5x) (8 + 5x) - (8-5x)²
= (8 - 5x) (8 + 5x) - (8-5x)(8-5x)
Facteur commun (8 - 5x)
= (8-5x)[ (8+5x) - (8 - 5x)]
= (8-5x) (8 + 5x - 8 + 5x)
= (8 - 5x) (10x)
64-25x²-(8-5x)² = 10x ( 8 - 5x)
Factorisons l'expression 49x^2+28x+4-25
49x^2+28x+4 = (7x)² + 2X7x X 2 + 2 ² = (7x + 2)²
49x^2+28x+4-25 = (7x + 2)² - 5²
= (7x + 2 - 5) ( 7x + 2 + 5)
= (7x - 3) ( 7x + 7)
49x^2+28x+4-25 = 7(7x - 3) ( x + 1)
