Answer:
1081
Step-by-step explanation:
Answer: -(x + 3)^2 = 3
Explanation:
-x^2 - 6x + 6 = 0
-x^2 - 6x = -6
-x^2 - 6x + 9 = -6 + 9
-(x + 3)^2 = 3
Answer:
I think the 3rd option but im not sure
Answer:
I think its y
Step-by-step explanation:
Hope that helps:)
Answer:
The half-life of the radioactive substance is of 3.25 days.
Step-by-step explanation:
The amount of radioactive substance is proportional to the number of counts per minute:
This means that the amount is given by the following differential equation:

In which k is the decay rate.
The solution is:

In which Q(0) is the initial amount:
8000 counts per minute on a Geiger counter at a certain time
This means that 
500 counts per minute 13 days later.
This means that
. We use this to find k.







So

Determine the half-life of the radioactive substance.
This is t for which Q(t) = 0.5Q(0). So







The half-life of the radioactive substance is of 3.25 days.