Bonjour,
Développer l'expression:
D= (5x-1)(5x-2)-(2x+3)(5x-1)
D= 25x²-5x-10x+2- (10x²+15x-2x-3)
D= 25x²-15x+2- 10x²-13x+3
D= 15x²-28x+5
Factoriser:
D= (5x-1)(5x-2)-(2x+3)(5x-1)
D= (5x-1)(5x-2-2x - 3) ***changement de signe
D= (5x-1)(3x-5)
Calculer D pour x= 5/3:
D= 15x²-28x+5
D(5/3)= 15(5/3)²-28(5/3)+5= 15(25/9)-140/3+5= 375/9-3(140)/9+9(15)/9
D(5/3)= 375/9- 420/9+ 135/9= 90/9= 10
