The equation is:
[tex]4c^2+7c-5=0[/tex]so we can use the cuadratic equation so:
[tex]\begin{gathered} c=\frac{-b\pm\sqrt[]{b^2-4(a)(c^{\prime})}}{2(a)} \\ \text{where} \\ a=4 \\ b=7 \\ c^{\prime}=-5 \end{gathered}[/tex]So if we replace in the equation we will have:
[tex]c=\frac{-7\pm\sqrt[]{7^2-4(4)(-5)}}{2(4)}[/tex]So we simplify to solve the problem so:
[tex]c=\frac{-7\pm\sqrt[]{129}}{8}[/tex]