Answer:
[tex]x_1=x_2=-\dfrac{2}{3}[/tex]
Step-by-step explanation:
For the quadratic equation [tex]ax^2+bx+c=0[/tex] the discriminant is defined as
[tex]D=b^2-4ac[/tex]
and the quadratic formula for the roots gives us two roots:
[tex]x_1=\dfrac{-b-\sqrt{D}}{2a}[/tex]
and
[tex]x_2=\dfrac{-b+\sqrt{D}}{2a}[/tex]
For the equation [tex]9x^2 +12x+4=0[/tex] use quadratic formula to find roots:
[tex]D=12^2-4\cdot 9\cdot 4=144-144=0[/tex]
So,
[tex]x_1=x_2=\dfrac{-12\pm \sqrt{0}}{2\cdot 9}=-\dfrac{12}{18}=-\dfrac{2}{3}[/tex]
