Resposta :
Para não admitir raízes reais, delta < 0.
kx² - 16 + 5 = 0
delta < 0
b² - 4ac < 0
(- 16)² + 4.k.5 < 0
256 + 20k < 0
20k < - 256
k < - 256/20
k < - 128/10
k < - 64/5
kx² - 16 + 5 = 0
delta < 0
b² - 4ac < 0
(- 16)² + 4.k.5 < 0
256 + 20k < 0
20k < - 256
k < - 256/20
k < - 128/10
k < - 64/5