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}](https://tex.z-dn.net/?f=%5Cbf%20h%28t%29%3D-8t%5E2-28t%2B60%5Cimplies%20%5Cstackrel%7Bh%28t%29%7D%7B0%7D%3D-8t%5E2-28t%2B60%0A%5C%5C%5C%5C%5C%5C%0A0%3D-2t%5E2-7t%2B15%5Cimplies%202t%5E2%2B7t-15%3D0%5Cimplies%20%282t%2B3%29%28t-5%29%3D0%0A%5C%5C%5C%5C%5C%5C%0A%5Cbegin%7Bcases%7D%0A2t%2B3%3D0%5Cimplies%202t%3D-3%5Cimplies%20%26t%3D-%5Cfrac%7B3%7D%7B2%7D%5C%5C%5C%5C%0At-5%3D0%5Cimplies%20%26%5Cboxed%7Bt%3D5%7D%0A%5Cend%7Bcases%7D)
clearly the seconds cannot be a negative unit, so is not -3/2.
Answer:
7/20
Step-by-step explanation:
of = multiply
1/2 x 7/10
1 x 7 = 7
2x 10 = 20
7/20 can not be reduced.
so, the answer will be 7/20
<h2>
<u><em>hope it helps </em></u></h2>
Answer:
The answer is 5/8
Step-by-step explanation:
Step 1 : Convert both fractions so they have the same denominator (bottom number in the fraction.)
1/4 = 2/8
So now were dealing with :
2/8 + 3/8 = ?
Step 2 : Add the numerators together to get the numerator for our answer.
2 + 3 = 5
When adding two fractions with the same denominator the denominator stays the same, so our answer is 5/8.
Hope this helps, please mark brainliest. :) Have a nice day.
Answer:
1350.61
Step-by-step explanation:
f(x)=1200(1.03^x)