a = 3
b = 0
c = -75
Δ = b² - 4 .a .c
Δ = 0² - 4 .3 .(-75)
Δ = 900
x = -b ± [tex]\sqrt{Delta}[/tex] /2 .a
x = 0 ± [tex]\sqrt{900}[/tex] /2 .3
x = 0 ± 30 /6
x' = 30 /6 = 5
x" = -30 /6 = -5
S = (5, -5)
