Okay, we know the price of the child's ticket (x), which is 5.75 dollars less than the adult's ticket.
Let's say that the price of the adult's ticket is a. Since the child's ticket is 5.75 less that the adult's ticket, we can write it this way:
a = 5.75 + x
Slope=(y2-y1)/(x2-x1)
=(4-7)/(2--3)
=3/5
(6,5)---------------(1,2)-------------------(x2,y2)
6+x2/2=1
5+y2/2=2
6+x2=2
x2=-4
y2=4-5
y2=-1
(-4,-1)
answer is C