Question

H(t)=-16t(t-3)+21 what the interval

Answer 1

Key:the time in seconds and h is the height in feet. t = sec (x-value) height (y-valie) h...n ({}) = - 16(3) 2. -16. -32. 4(4)=-16(4) +128(4). 4 (4)=256 ft. (must include 21)

Thats all I got

Good luck :)

Answer 2

Explanation:

Set h=0 for ground height, then solve for t

-16t^2 -20t +240 = 0

divide by -4

4t^2 +5t - 60 = 0

use the quadratic formula

t= -5/8 + or - (1/8)square root of (25 +4(4)(60)). Ignore the negative square root

=-5/8 + (1/8)sqr(960+25)

= -5/8 + (1/8)sqr(985)

=-5/8 + (1/8)sqr(5(197))= slightly less than -5/8 +(10/8)(sqr10) = about -5/8 +32/8 = 27/8 = 3.3 seconds