Answer:
-3 is the value of the location where the line crosses the y-axis,and is commonly referred in the slope-intercept form of a line "the intercept". Now it may be your teacher expects you to answer this as the point on the plane where the y-intercept occurs, and that should be the point (0, -3). Make sure you follow your teacher's notation.
Step-by-step explanation:
Re-write the equation given in slope=intercept form by isolating the variable "y" on one side of the equation and expressing the rest in slope*x + y-intercet form:

which tells us that the slope of the line is -2 and it y-intercept is "-3".
Now, watch out because you may be asked to write the actual coordinates of the y-intercept, which are: (0, -3)
giving the x-coordinate 0 and the y-value where the line crosses the y-axis.