Question

A baseball player has hit a ball. The height, y, of the ball x seconds after it is hit is given by y= -16x^2 + 80x + 3.

Answer 1

So, I need to find the time it takes the ball to reach it's make height; it's max height, and the time it takes the ball to land on the ground.

y= -16x^2 + 80x + 3
I can use the vertex formula to find the time of it's max height

vertex = -b/2a, -80/2(16) = -80/32

Vertex or time, then is equal to 2.5 seconds. Is the first part right?

Answer 2

@Miracrown , @hartnn , @ganeshie8

Answer 3

@wio

Answer 4

@dan815

Answer 5

y= -16x^2 + 80x + 3

Take 5/2

y = -16(5/2)^2 + 80(5/2) + 3
y = -16(25/4) + 80(5/2) + 3
y = -100 + 200 + 3
y = 103

So my points are (2.5, 103)... 2.5 being my time and 103 being my max height.

Answer 6

i guess there is a typo in first part. you forgot the negative sign `a=-16` -80/32 would be negative 5/2
it's \[\frac{ -80 }{ 2(-16) }=\frac{ -80 }{ -32 }=\frac{ 5 }{ 2 }\]

Answer 7

2nd part is correct y =103 ft
(2.5 , 103) is the vertex point(max) \(\huge\color{green}{\checkmark}\)

Answer 8

3rd part `the time it takes the ball to land on the ground` (x-intercept)
pretty sure you can solve this one too. :=)
goodluck!\o^_^o/