Answer:
<em>(a) 40 milligrams</em>
<em>(b) 1.21 milligrams</em>
Step-by-step explanation:
<u>Exponential Function</u>
It's commonly used to model real situations in life, like this one proposed in the question where the number of milligrams of a drug D(h) in a patient's bloodstream h hours after the drug is injected is modeled by the following function.

(a) The initial amount injected to the patient can be found when h=0

Initial amount: 40 milligrams
(b) Let's plug h=7
D(7) =40e^{-0.5(7)}=40e^{-3.5}=1.21
The amount in the bloodstream after 7 hours is 1.21 milligrams
2/3x +12/3 =7
2/3x + 4 =7
2/3x=7-4
2/3x=3
x=3*3/2
x=3
10y + 70= 12y
12y-10y=70
2y=70
y=70/2=35
0 hundreds<span> is equal to 9000. To find the number of 10's in 9000, simply divide them 9000/10 = 900. Comments; Report</span>
составим уравнение
11х=9х+124
2х=124
х=62
проверим ответ
682=558+124
тогда, общее количество детей
682+558=1240
450 divided by 2 is 225. 225-50=175. 225+50=275
John has 275 and Andrew has 175.
In order to get this answer, first you divide the whole number by 2. Then you get the number 225. You then have to subtract 50 from 225 because John gets 50 more than Andrew. Then for John, you have to add 50 to 225. To self-check the answer, here is the formula: 175+275=450. Remember that on these kind of word problems, you first divide the whole. Then subtract and add the number that one person gets more than the other person.