A ball is thrown in the air from a ledge. It's height in feet represented by f(x)=16(x^2-6x-7), where x is the number of seconds since the ball has been thrown. The height of the ball is 0 feet when it hits the ground. How many seconds does it take the ball to reach the ground?
Accepted Solution
A:
Answer:Step-by-step explanation:Since we know that the height is 0, we can figure out how long it took the ball to reach the ground by setting [tex]f(x) = 0[/tex] and solving for [tex]x[/tex]:[tex]f(x) = 16(x^{2} - 6x - 7)[/tex][tex]0 = 16(x^{2} - 6x - 7)[/tex][tex]0 = x^{2} - 6x - 7[/tex][tex]0 = (x - 7)(x + 1)[/tex][tex]x = -1, 7[/tex]Because time can only be positive, the answer is 7 seconds.