A2-mi cab ride costs $5.25. a 5-mi cab ride costs $10.50. how much does a 3.8-mi cab ride cost?
a. $14.00
c. $8.40
b. $10.75
d. $6.30the cost of 3.8-mi cab ride is: $8.40. ***x1 = 2; y1 = 5.25 x2 = 5; y2 = 10.50 m=y2-y1/x2-x1 m=10.50-5.25/5-2= 1.75 the cost of a 3.8 mi cab ride, [ substitute 3.8 for x and find y y = 1.75(3.8) + 1.75 y = 6.65 + 1.75 y = $8.40 for 3.8 mi ride ]

What I did to solve this is finding the equation of the line using slope intercept form y is the cost of the ride which increases as you increase mileage or move along the X axis. My points are (2, 5.25) and (5,10.5) 
y=mx+b 
m=y2-y1/x2-x1 
m=(10.5-5.25)/(5-2) 
m=5.25/3=1.75 or 7/4 

y=7/4x+b enter one point for the values of x and y to find b 
10.5=(1.75X5) + b 
10.5=8.75 + b 
b=1.75 

The equation of the line is y=7/4x+1.75 (I also double checked using the second point) 

Then all you have to do is enter the mileage 3.8 for the value of X and solve for y 
y=(7/4 X 3.8) + 1.75 
y=6.65+1.75 
y=8.4 The cab ride for the 3.8mile trip is $8.4 
I hope this helps