On wet, level pavenment

Question

On wet, level pavement, the stopping distance, d in feet, for a car traveling at x miles per hours can be estimated by d(x)=1/9 x2+10/3. Use the function to approximate the speed of the car that takes 375 feet to stop.

 

 

x2=x-squared 

 

the slashes indicate division

 

Write an equation and solve

Answer 1

375=1/9x^2 +10/3

 

Multiply the equation by 9.

 

x^2+30=3375 then subtract both sides by 30

x^2=3345 then take square root

x=57.8