When you have an inequality the correct form to write it in a standrad form is:
You have a dotted line it means that the result of the inequality doesn't include the value in the line just the values that are less than: (As you have the part below the line shaded)
Then so, the slope m= 12/3
The b is the point that takes y when x=0, we can see it is b=-2
Then the final standard form of this inequality is: