c^2+3c+2.16=0
Use Quadratic Formula
\(x = {-b \pm \sqrt{b^2-4ac} \over 2a}\)
\(x = {-3 \pm \sqrt{3^2-4(1)(2.16)} \over 2(1)}\) = (-3 +- .6)/2 = -1.2 and -1.8