The distance d (in feet) that it
takes a car to come to a complete stop can be modeled
by d = 0.05s^2 + 2.2s, where s is the speed of the car
(in miles per hour). A car has 168 feet to come to a
complete stop. Find the maximum speed at which the
car can travel.

40 mph

Step-by-step explanation:

To find the maximum speed at which the car can travel, as the distance it requires to stop is 168 feet, we just need to use the value of d = 168 in the equation, and then find the value of s:

168 = 0.05s^2 + 2.2s

0.05s^2 + 2.2s - 168 = 0

Using Bhaskara's formula: we have:

Delta = 2.2^2 + 4*0.05*168 = 38.44

sqrt(Delta) = 6.2

s1 = (-2.2 + 6.2)/0.1 = 40 mph

s2 = (-2.2 - 6.2)/0.1 = -84 mph (a negative value does not make sense as 's' is the speed of the car)

So the maximum speed of the car is 40 mph

let's solve your equation step-by-step.

4x+2=2x+12

step 1: subtract 2x from both sides.

4x+2−2x=2x+12−2x

2x+2=12

step 2: subtract 2 from both sides.

2x+2−2=12−2

2x=10

step 3: divide both sides by 2.

2x

2

=

10

2

x=5

step-by-step explanation: