Aball is thrown into the air with an upward velocity of 80 feet per second. the function h = -16t2 + 80t models the height h, in feet, of the ball at time t, in seconds. when will the ball reach the ground?

A ball is thrown vertically upward from ground level with an initial velocity of 80 feet per second. The ball's h height after t seconds is given by the equation h = −16t^2 + 80t. How long will it take for the ball to hit the ground?

A) 5 Seconds

B) 6 Seconds

C) 7 Seconds

D) 8 Seconds

Step-by-step explanation:

The correct answer for this problem is

A) 5 Seconds

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1