How to do this problem 3(4x-2) equals 12x plus 1

"Do the problem" means find out what  number 'x' must be
in order to make the equation a true statement.

You said                                                     3 (4x - 2)  =  12x + 1

Eliminate the parentheses on the left:        12x - 6  =  12x + 1

Subtract  12x  from each side:                           - 6  =        + 1

Here's where we stop.  There is no value for 'x' that can make  -6 = 1 .

The original equation has no solution.