Question

what is |3x-12| greater than or equal to 12?

Answer 1

An absolute value inequality of this type,
|A| >= b
where A is an expression in x, and b is a positive number is solved by changing it into two inequalites separated by the word "or"
A >= b or A <= -b

In this case, the expression is x is 3x - 12, so to solve
|3x - 12| >= 12, solve these two inequalites:
3x - 12 >= 12 or 3x - 12 <= -12