bonjour
Je suppose qu’il faut factoriser et non résoudre ?
x²−4−(3x−1)(x+2)=
= x^2 - 2^2 - (3x - 1)(x + 2)
=> a^2 - b^2 = (a - b)(a + b)
= (x - 2)(x + 2) - (3x - 1)(x + 2)
=> facteur commun (x + 2)
= (x + 2)(x - 2 - (3x - 1))
= (x + 2)(x - 2 - 3x + 1)
= (x + 2)(-2x - 1)
x²−5=
= x^2 - (V5)^2
=> a^2 - b^2 = (a - b)(a + b)
= (x - V5)(x + V5)
Avec V5 : racine de 5
3(x−2)²+(x−2)(8−4x)=
=> facteur commun : (x - 2)
= (x - 2)[3(x - 2) + 8 - 4x]
= (x - 2)(3x - 6 + 8 - 4x)
= (x - 2)(-x + 2)
= (x - 2) * (-1)(x - 2)
= -(x - 2)^2
