A vertical line has an equation of the form x = k, where k is the x-coordinate of all points on the line.
You have a vertical line. It passes through the point (-3, 0), so for this line, k = -3.
The vertical line has equation x = -3.
The line is dashed, not solid, so you have either < or >, but not <= or >=.
Also, notice the shading is to the left of x = -3, so all values of x are less than -3.
The inequality is
x < -3