Question 987006
The length of a car's skid mark in feet is given by L=0.042s2−0.199s+0.264, where 
 s is the car's speed in miles per hour.
 If the length of a skid mark is 110feet, find the speed in miles per hour the car was traveling.
:
0.042s^2 − 0.199s + 0.264 = 110
0.042s^2 − 0.199s + 0.264 - 110 = 0
0.042s^2 − 0.199s - 109.736 = 0
Using the quadratic formula: {{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
where in this equation a = .042; b = -.199; c = -109.736
I got a positive solution of:
s = 53.5391 mph
:
See if that is what you get.