Answer
$$y=\frac{1}{2}x
.$$
Work Step by Step
The point-slope form of a line is given as:
$$y-y_1=m(x-x_1)$$
We plug in the given point and slope and solve for $y$:
$$y+3=\frac{1}{2}(x+3)\Longrightarrow y=\frac{1}{2}x+3-3=\frac{1}{2}x
.$$