Question

If an object is projected upward with an initial velocity of 129 ft per​ sec, its height h after t seconds is h equals -16 t squared +129t h=−16t2+129t. Find the height of the object after 4 seconds.

Answer 1

This equation should be written h(t) = -16t^2 + 129t.  After 4 sec, the height of this object is

h(4) = -16(4)^2 + 129(4) = -256 + 516 = 260 feet.

Answer 2

To find the height of the object after 4 seconds, just input the 4 where t is located.

So
$h=-16t^2 = 129t$
$h=-16(4)^2 = 129(4)$
Now just solve for h