Verified answer

[tex]\displaystyle\bf\\4x^{2}+12x+9=0 \ |:4\\\\x^{2} +3x+2,25=0\\\\Teorema \ Vieta \ :\\\\x_{1} + x_{2} =-3\\\\x_{1} \cdot x_{2} =2,25\\\\x_{1} = x_{2} =-1,5[/tex]