Répondre :

(5X- 4)² - (X+1)(X-2)
=25x²-40x+16-(x²-2x+x-2)
=25x²-40x+16-x²+2x-x+2
=24x²-39x+18
Bonsoir

(5X- 4)² - (X+1)(X-2)
(25x² - 20x +16) - (x² -2x +x -2)
25x² -20x +16 -x² +2x -x +2
24x² -39x +18