57.50 - 8 = 49.50 more she needs to save
49.50 / 4.50 = 11
she needs to save for 11 weeks
The slope of the line is

It can be found from any two points that fall on a line by using the formula

2 is x or y from the second point and 1 is x or y from the first point
For example in that problem the first point is -2,0 and the second one is 0,3
A real number = x or any variable
It would be x ≥ 5.5