Me ! sandy is observing the velocity of a runner at different times. after one hour, the velocity of the runner is 4 km/h. after two hours, the velocity of the runner is 2 km/h. part a: write an equation in two variables in the standard form that can be used to describe the velocity of the runner at different times. show your work and define the variables used. part b: how can you graph the equations obtained in part a for the first 4 hours?

Use the given times and velocities to make two points:  (1,4) and (2,2)   

Part A: 

Slope is the change in Y over the change in X from the two pints you made:

 Slope =  (2-4) / (2-1 )= -2

Now you have the slope, calculate the Y-intercept

y = -2x + b

Using (1,4)

4 = -2(1) + b = 4 =-2 +b. b = 6

 Equation is: y = -2x+6

Part B:

using the above equation replace x with 1, 2, 3, and 4 and solve for the Y

 then plot those onto a graph

area of part 1:

a1=base*height/2=(8+2)*(8-2-2-1)/2=10*3/2=15 ft^2

area of part 2:

a2=length*width=(8+2)*1=10 ft2

area of part 3:

a3=length*width=8*2=16 ft2

total shaded area : a1+a2+a3=41 ft2

total area of the reactangle : a=16*8=128 ft2

total area of the nonshaded region : 128-41=87 ft2

37

step-by-step explanation: