Sam is observing the velocity of a car at different times. after three hours, the velocity of the car is 53 km/h. after six hours, the velocity of the car is 62 km/h. part a: write an equation in two variables in the standard form that can be used to describe the velocity of the car at different times. show your work and define the variables used. part b: graph the equation obtained in part a for the first seven hours

Standard form of linear rquation : y=mx+b 

first find out the gradient 

gradient = rise/run 
gradient =(y2-y1)/(x2-x1) 
  the velocity of the car is 53 km/h.   the velocity of the car is 62 km/h" 
(x1,y1) = (3,53) 
(x2,y2) = (6,62) 

sub values back into the equation 
m = (62-53)/(6-3) 
m = 9/3 
m = 3 

now we use a point-slope form to find the the standard form 
y-y1 = m(x-x1) 
 
y-53 = 3(x-3) 
y-53 = 3x - 9 
y = 3x - 9 + 53 
y = 3x + 44 

y is the velocity of the car, x is the time.