Synaesthesia is the neurological mixing of the senses. A synaesthete may for example hear[?]colours, see sounds, and taste tactile sensations. While this may happen in a person who has got autism, it is by no means exclusive to autistics.
... and it is impossible to divide by it.)
The symbol
<math>\pm \sqrt {b^2-4ac}</math>
in the formula should be understood as "either of those element(s) of ...