Answer:
a)
, b)
, c)
, d) 
Step-by-step explanation:
a) Let assume an initial mass m decaying at a constant rate k throughout time, the differential equation is:

b) The general solution is found after separating variables and integrating each sides:

Where
is the time constant and 
c) The time constant is:


The particular solution of the differential equation is:

d) The amount of radium after 300 years is:

1 foot is 12 inches. So just divide 81 by 12.
81/12 = 6.75
So your answer is 6.75 feet.
Answer:
4xy
Step-by-step explanation:
Answer:
c = 28
Step-by-step explanation:
Solve for c by simplifying both sides of the equation, then isolating the variable.
Answer: y = 52
Explanation:
13/3=4 1/3
4 1/3 times 12 = 52
Ratio explanation
(Times 4 1/3) 12:3 (divided by 4 1/3
New Ratio- 52:13