For inline equations, use \( and \).

This equation code \( ax^2 + \sqrt{bx} + c = 0 \) renders as \( ax^2 + \sqrt{bx} + c = 0 \)

For centered equations, use \[ and \].

This equation code \[ x = {-b \pm \sqrt{b^2-4ac} \over 2a} \] renders as:

\[ x = {-b \pm \sqrt{b^2-4ac} \over 2a} \]