Answer:
5.1 days
Step-by-step explanation:
Given in the question,
initial amount of substance = 34 grams
k-value = 0.137
To find the half life of this substance we will use following formula

here N(0) is initial amount of substance
t is time in days
Plug values in the formula

1/2 = e^{-0.137t}
Take logarithm on both sides
ln(1/2) = ln( e^{-0.137t})
ln(1/2) = -0.137t
t = ln(1/2) / -0.137
t = 5.059
t ≈ 5.1 days (nearest to tenths)
Answer:
3.8
Step-by-step explanation:
Answer:
12.54
Step-by-step explanation:
5>0
Answer:
Center: (4,8)
Radius: 2.5
Equation: 
Step-by-step explanation:
It was given that; the endpoints of the longest chord on a circle are (4, 5.5) and (4, 10.5).
Note that the longest chord is the diameter;
The midpoint of the ends of the diameter gives us the center;
Use the midpoint formula;

The center is at; 
To find the radius, use the distance formula to find the distance from the center to one of the endpoints.
The distance formula is;




The equation of the circle in standard form is given by;

We substitute the center and the radius into the formula to get;


Make y the subject in both equations



For the second equation

The two equations are parallel because they have the same gradient or slope but different y intercepts.
This type of equations have no solution because they will never intersect.

The correct answer is C