[tex]4x^2 + 3 = -12x[/tex]
[tex]4x^2 + 12x + 3 = 0[/tex]
Apply quadratic formula:
[tex]x = \dfrac{-b \pm \sqrt{b^2 - 4ac} }{2a} [/tex]
[tex]x = \dfrac{-(12) \pm \sqrt{(12)^2 - 4(4(3))} }{2(4)} [/tex]
[tex]x = -2.72 \ or \ -0.28 [/tex]
[tex]\boxed {\boxed{\text{Answer: x = -2.72 or -0.28 } }}[/tex]