Respuesta :

hello :
5x²+12x+8 =0 
delta = 12²-4(5)(8) = -16 =  16i²......(i² = 1)
delta = (4i)²
x1 = (-12+4i)/2          x2 = (-12-4i)/2 
x1 =-6+2i         x2 = -6-2i

Answer:

[tex]S=\{ \frac{-6}{5}+\frac{2}{5}i, \frac{-6}{5}-\frac{2}{5}i\}[/tex]

Step-by-step explanation:

[tex]5x^2+12x+8 =0[/tex]

We are going to use the general formula to find the solution. That formula is

[tex]x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}[/tex]

where a= 5, b=12 and c=8. Then

[tex]x = \frac{-12\pm\sqrt{144-4(5)(8)}}{10}[/tex]

[tex]x = \frac{-12\pm\sqrt{144-4(5)(8)}}{10}[/tex]

[tex]x = \frac{-12\pm\sqrt{-16}}{10}[/tex]

[tex]x = \frac{-12\pm4i}{10}[/tex]

[tex]x_1 = \frac{-12+4i}{10}[/tex]

[tex]x_1 = \frac{-6}{5}+\frac{2}{5}i[/tex]

[tex]x_2 = \frac{-12-4i}{10}[/tex]

[tex]x_2 = \frac{-6}{5}-\frac{2}{5}i[/tex].

Then, the solution set is [tex]S=\{ \frac{-6}{5}+\frac{2}{5}i, \frac{-6}{5}-\frac{2}{5}i\}[/tex]