In order to be parallel to a line, two lines must have the same slope. The slope of y=3x+2 is 3. So the slope of the other equation has the be 3. y=3x+b. Now we can plug in the x and y values given by the point to calculate the b in the equation.
-3=3(-1)+b
-3=-3+b
b=0
So the equation is y=3x