What number line represents the solution set for the inequality 3x < –9?

The solution set of the given inequality is:

                         (-∞,-3)

We are given a inequality in terms of the variable x by:

We divide both side of the inequality by 3 to obtain the new expression as:

This means that the graph of such a inequality is the set of all the real value which are strictly less than -3( since the inequality is strict)

Hence, the solution set in set-Builder form is:

   ={all x belonging to real numbers| x<-3}

and in interval form the solution is: (-∞,-3)

d. vertex

step-by-step explanation: