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

B. because the 7 represents "seven times", x represents "a number", 12 represents "plus twelve", and -4 represents "minus four"