Respuesta :

Answer:

3x^2+12=0

3x^2=0-12

3x^2=-12

X^2=12/3

x^2=4

X= root under4

x=2

Answer:

Q3: x1=2+i, x2=2-i Q4: x1=-3/2+i, x2=-3/2-i

Step-by-step explanation:

[tex]x^{2} - 4x + 5 =0[/tex]

( [tex]4[/tex]± [tex]\sqrt{16 - 4*1*5}[/tex] ) / [tex]2[/tex] = (

x1= 2+i

x2= 2-i

[tex]2x^{2} +6x + 5 =0[/tex]

( [tex]-6[/tex] ± [tex]\sqrt{36 - 4*2*5}[/tex] ) / [tex]4[/tex] = (-6 ± [tex]\sqrt{-4}[/tex] )/4= (-3 ± i)/2

x1 = -3/2 +i

x2 = -3/2 -i