So, h(t) is how far is Daniel's head from the surface of the water, namely the surface itself is when the height is nill, so his head is at the surface and the height of it is just 0, thus h(t) = 0. Namely, what is "t" when h(t) is 0?

$\bf h(t)=-8t^2-28t+60\implies \stackrel{h(t)}{0}=-8t^2-28t+60
\\\\\\
0=-2t^2-7t+15\implies 2t^2+7t-15=0\implies (2t+3)(t-5)=0
\\\\\\
\begin{cases}
2t+3=0\implies 2t=-3\implies &t=-\frac{3}{2}\\\\
t-5=0\implies &\boxed{t=5}
\end{cases}$

clearly the seconds cannot be a negative unit, so is not -3/2.

6 0

2 years ago

jonah wants to buy two copies of a book. which algebraic expression could jonah use to find the value of the items

Bezzdna [24]

2x because its 2 times the price of the book (x)

5 0

3 years ago

What is the answer to this question?

blondinia [14]

The area of the shape is 230 cm.

4 0

2 years ago

Find the slope and y intercept

zepelin [54]

Answer:

slope = -1

y intercept (0,-2)

Step-by-step explanation:

We can use the two points to find the slope

(-4,2) and (1,-3)

m = ( y2-y1)/(x2-x1)

= (-3 -2)/(1 - -4)

= -5 /(1+4)

= -5/5

- 1

The y intercept is where it crosses the y axis

y intercept is (0,-2)

5 0

2 years ago