Answer:
x xjjkdjbdnnxuhxnmdujxnxlxuxbx
Answer:
a. 
b. 
Step-by-step explanation:
First, we need tot find a general expression for the amount of caffeine remaining in the body after certain time. As the problem states that every hour x percent of caffeine leaves the body, we must substract that percentage from the initial quantity of caffeine, by each hour passing. That expression would be:

Then, to find the amount of caffeine metabolized per hour, we need to differentiate the previous equation. Following the differentiation rules we get:

The rate is negative as it represents the amount of caffeine leaving the body at certain time.
Answer:
0.9 x 81
Step-by-step explanation:
0.9 is actually 0.90 and 90 is greater than 75
<h2>
<u>Sol</u><u>ution</u><u>:</u></h2>
Equation: x² + 10x + 21
<u>Step</u><u> </u><u>1</u><u>:</u> Find two numbers that can add up to 10 and be multiplied to 21. We have: 7 & 3, in the sense that 7+3=10, and 7×3=21. Replacing 10 with 7+3, the equation is now → x² + 7x + 3x + 21
<u>Step</u><u> </u><u>2</u><u>:</u> Get the new equation bracketed → (x² + 7x) (+3x + 21)
<u>Step</u><u> </u><u>3</u><u>:</u> Use 'x' in the equation. For the first part, we have 'x'. x² = x × x so, bring out one x out side the bracket, divide 7x by = 7 → x (x +7). Do the same for the second part by dividing 21 by 3 = 7, and then bringing out 3 from the bracket → 3 (x + 7).
Bringing everything together, we have: x(x+7) +3(x+7) → (x+3) (x+7)
<h3>
<u>Final</u><u> </u><u>ans</u><u>wer</u><u>:</u></h3>
(x+3) (x+7)
<h3 />
Step-by-step explanation:
1) 7/23 + 11/23 + 9/23
7+11+9/23
27/23
= 1 4/23
2) 2 5/7 + 9 4/7
11 9/7
= 11.12
3) 9/20 + 3/5
9+12/20
21/20
= 1 1/20 or 1.05