Salut je suis coincé quelqu’un peut m’aider

bonsoir

f (x) = ( - 1 + 3 x )² - ( - x + 2 )²

f (x) =  1 - 6 x + 9 x² - ( x² - 4 x + 4 )

f (x) =  9 x² - 6 x + 1 - x² + 4 x - 4

f (x) = 8 x² - 2 x - 3

f (x) =  ( - 1 + 3 x - x + 2 ) ( - 1 + 3 x + x - 2 )

f (x) = ( - 2 x + 1 ) ( 4 x - 3 )

f (x) = 8 ( x - 1/8)² - 25 /8

f (x) =  8 ( x² - 2 x /8 + 1/64 ) - 25/8

f (x) =  8 x² -  16 x /8 + 8 /64 - 25/8

f (x) = 8 x² - 2 x +  1/8 - 25/8

f (x) = 8 x² - 2 x - 24 /8

f (x) = 8 x² - 2 x - 3

Réponse :

1) 1-6x+9x^2-(x^2-4x+4)

= 8x^2-2x- 3

2) a^2 -b^2

= (a+b) (a-b)

= (-1+3x+(-x+2)) (-1+x-(-x+2))

= (2x+1) ( 2x+1)

3) 2x X 4x -2x X 3 +4x -3

= 8x^2-6x+4x-3

= 8x^2-2x-3

soit 8(x-1/2)^2-25/8