A. find a slope-intercept equation for line a. b. find a point-slope equation for line b.

The generic equation of the line is given by:
 
 Equivalently:
 
 Where,
 m: slope of the line
 b: cutting point with the y axis
 (xo, yo): ordered pair that belongs to the line
 
 For line A:
 The slope is given by:
 
 
 The cut point with the y axis is:
 
 Substituting values we have:
 

 For line B:
 The slope is given by:
 
 
 
 
 Then, the equation of the line is:
 

 
 Option A

500 dollars and its probably more than that

A. is the answer in this question