Solve this equation
4-2x-12-2x+1

This is not an equation because it lacks an equal signso the only thing we can do here is combine like terms.
4 - 2x - 12 - 2x + 1 =
-4x - 7

1) Gather like terms 4+(-2x-2x)-12+1                                                                   2) Simplify 4-4x-12+1                                                                                            3) Simplify -4x-7                                                                                                      4) Cannot be simplified any further.

Letter a i would say