Réponse :
(x-1)(x+5) = x² + 5x - x - 5 = x² + 4x - 5
x² = - 4x + 5
x = racine carré de (-4x +5)
(4x + 5) (2x + 6) = 8x² + 24x + 10x + 30 = 8x² + 34x + 30
6x² = - 34x - 30
x² = -34/6 - 30/6
x² = -17/3 - 5
x = racine carré de (-17/3 -5)
(5u + 1)(2 - 3u) = 10u - 15 u² + 2 - 3u = - 15u² + 12u + 2
15u² = -12u - 2
u² = -12u/15 - 2/15 = -4u/5 -2/15
u = racine carré de (-4u/5 - 2/15)
(-3 + n)(-2n - 5) = + 6n + 15 - 2n² - 5n = -2n² + n + 15
-2n² = -n - 15
n² = n/2 +15/2
n = racine carré de (n/2 + 15/2)
Explications étape par étape
