Add them around 8 and -4 for smallest and around 1 + 3 and 2 + 8 for highest
For this graph the equation is x= -3
Because in the coordinates you gave, all the x values are -3 telling me that the line is a straight vertical line passing through the -3 x-axis and has no y-intercept as it's a vertical line, not diagonal, so it's not passing through the y-axis. Plus because of this too this line has no gradient.
She would need to buy 10 additional bags.