Bonjour
calculer sans calculatrice :
A = 5,3^2 - 4,7^2
expression du type :
a^2 - b^2 = (a - b)(a + b)
A = (5,3 - 4,7)(5,3 + 4,7)
A = 0,6 * 10
A = 6
developper :
A = (x - 2/3)(x - 4/3)
A = x * x - x * 4/3 - 2/3 * x + 2/3 * 4/3
A = x^2 - 4x/3 - 2x/3 + 8/9
A = x^2 - 6x/3 + 8/9
A = x^2 - 2x + 8/9
