When $a\ne 0$, there are two solutions to $(a{x}^2+bx+c=0)$ and they are

$$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$$

Maxwell's equations:

equation	description
$\mathrm{\nabla }\cdot \overrightarrow{\mathbf{B}}=0$	divergence of $\overrightarrow{\mathbf{B}}$ is zero
$\mathrm{\nabla }\times \overrightarrow{\mathbf{E}}+\frac{1}{c}\frac{\partial \overrightarrow{\mathbf{B}}}{\partial t}=\overrightarrow{\mathbf{0}}$	curl of $\overrightarrow{\mathbf{E}}$ is proportional to the rate of change of $\overrightarrow{\mathbf{B}}$
$\mathrm{\nabla }\times \overrightarrow{\mathbf{B}}-\frac{1}{c}\frac{\partial \overrightarrow{\mathbf{E}}}{\partial t}=\frac{4\pi }{c}\overrightarrow{\mathbf{j}}\mathrm{\nabla }\cdot \overrightarrow{\mathbf{E}}=4\pi \rho$	wha?