Anastasia hits her golf ball off the tee. The height of the golf ball is modeled by the function f(x) =-5x^2+25x+1, where x is the number of seconds after the golf ball is hit. How long is the golf ball in the air? ​

9514 1404 393

  5.04 seconds

Step-by-step explanation:

Assuming the ball is in the air until f(x) = 0, we want to find x such that ...

  0 = -5x² +25x +1

  0 = x² -5x -1/5 . . . . . divide by -5

  1/5 = x² -5x . . . . . . . add 1/5

  1/5 +25/4 = (x² -5x +25/4) . . . . complete the square

  129/20 = (x -5/2)² . . . . . . . . . . write as a square

  x = 5/2 +√(129/20) ≈ 5.039685 . . . . square root, add 5/2

The ball stays in the air about 5.04 seconds.

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.

c

step-by-step explanation: