k(x)=x+3 is a linear function (straight line). Next, find out what the graph looks like.
When x=-3, k(x)=0. This is the x-intercept (horizontal axis).
When x=0, k(0)=3. This is the y-intercept (vertical axis).
The line drawn through the intercepts, that is, (-3,0) and (0,3), is the graph of k(x). The line has a 45° slope if both axes are drawn to the same scale.