Then the command colorblue sets the blue colour for the current block of text. The double backslash works as a newline character. L a T e X allows two writing modes for mathematical expressions.
How to write mathematical notations in LaTeX.
Otherwise use equation environment in order to print the equation without a line number. The colour of a second block of text delimited by and is set to red with the command colorred then a 05mm-thick horizontal ruler is inserted by rulelinewidth05mm. Text within this box cannot be broken across lines. An inline expression occurs in the middle of the text.