Given :
The percent of concentration of a certain drug in the bloodstream x hours after the drug is administered is given by
.
To Find :
Find the time at which the concentration is a maximum. b. Find the maximum concentration.
Solution :
For maximum value of x, K'(x) = 0.

Since, time cannot be negative, so ignoring x = -3 .
Putting value of x = 3, we get, K(3) = 15/( 9 + 9) = 5/6
Therefore, maximum value drug in bloodstream is 5/6 at time x = 3 units.
Hence, this is the required solution.
X=27 and y=11
if you let each number equal x and y we know the sum is 38 so x+y=38
and the smaller is 16 less than the larger
. so if we say the smaller number is 7 then x-16=y
these can be solved as a simultaneous equation. x+(x-16)=38
2x-16=38
2x=54
x=27
(27)-16=y
y=11
so the answer is x=27 y=11
Your total after tax is $30.12
A 20% tip is approximately $5.50 ($5.67)
One battery costs $1.44.
The unit rate would be

To get that answer, you would have to divide 13 ÷ 9.
I'm not sure if this is what you were looking for, but if it was, I hope I helped! :-)
I think the answer would be true