Richard throws a stone over a bridge into the river below. The stone's height, in meters above the water, x seconds after it is thrown is modeled
by h () = = -5 (x – 8) (x + 4).
a.) How many seconds after being thrown will the stone meet its maximum
height?
b.) What is the maximum height of the stone?

a.) In 1 second stone reach its maximum height

b.) 45 m

Step-by-step explanation:

v=  

2

u

=u−gt

=u−  

2

3

g

t=1.5s

u=30m/s

h=  

2g

u  

2

h=  

2×10

30×30

=45m

add 5 subtract 1

step-by-step explanation:

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4