Sagot :
Bonsoir,
Tu appliques "le produit en croix" (x * y' - x' * y = 0)
1) 2 * 5 - n * (-8) = 0
10 + 8n = 0
8n = -10
n = - 10/8 = - 5/4 = -1,25
2) 3 * (-3) - (-n) * n = 0
-9 + n² =
(n + 3)(n - 3) = 0
n + 3 = 0 ou n - 3 = 0
n = -3 ou n = 3
3) n * (n+ 1) - 3n * 5 = 0
n² + n - 15n = 0
n² - 14n = 0
n(n - 14) = 0
n = 0 ou n - 14 = 0
n = 0 ou n = 14
Tu appliques "le produit en croix" (x * y' - x' * y = 0)
1) 2 * 5 - n * (-8) = 0
10 + 8n = 0
8n = -10
n = - 10/8 = - 5/4 = -1,25
2) 3 * (-3) - (-n) * n = 0
-9 + n² =
(n + 3)(n - 3) = 0
n + 3 = 0 ou n - 3 = 0
n = -3 ou n = 3
3) n * (n+ 1) - 3n * 5 = 0
n² + n - 15n = 0
n² - 14n = 0
n(n - 14) = 0
n = 0 ou n - 14 = 0
n = 0 ou n = 14