Add 12 to all three sides:
Divide all three sides by -4, and since we are
dividing by a negative number, the inequalities
reverse their direction:
It is most common to leave final inequalities in terms of
≤ and < rather that ≥ and >
Since we want interval notation, we plot it on a number line
-----o=======●---------------------
-6 -4 -3 -2 -1 -0 1 2 3
The interval notation is an abbreviation for the graph on a number line:
(-4,-2]
Edwin