The last 2 options are correct
The question is incomplete, here is the complete question:
Recall that m(t) = m.(1/2)^t/h for radioactive decay, where h is the half-life. Suppose that a 500 g sample of phosphorus-32 decays to 356 g over 7 days. Calculate the half life of the sample.
<u>Answer:</u> The half life of the sample of phosphorus-32 is 
<u>Step-by-step explanation:</u>
The equation used to calculate the half life of the sample is given as:

where,
m(t) = amount of sample after time 't' = 356 g
= initial amount of the sample = 500 g
t = time period = 7 days
h = half life of the sample = ?
Putting values in above equation, we get:

Hence, the half life of the sample of phosphorus-32 is 
Answer:
did u forget to add the actual question
Step-by-step explanation:
Answers:

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Step-by-step explanation:
<h2>8.</h2>

Dividing both sides by n · R:

<h2>9.</h2><h2 />

Multiplying both sides by 1000:

Dividing both sides by tc:

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Answer:
I dont see a question.
Step-by-step explanation: