the weight of the substance after 28 years is 8 grams.
<h3>How to determine the amount</h3>
We have that the half life of a substance is defined as the time required for the substance to decrease by half
The formula for calculating the half - life of a material is given as;

Where
- N(t) is final amount
- No is the initial amount = 128 grams
- t1/2 is the half life = 7 years
- t is the time elapsed = 28 years
Substitute into the formula
N(t) = 128 × (0. 5) ^28/ 7
N (t) = 128 × ( 0. 5) ^ 4
N(t) = 128 × 0. 0625
N(t) = 8 grams
Thus, the weight of the substance after 28 years is 8 grams.
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Answer:
1. 9/16
2. 39/250
3. 12/15
Step-by-step explanation:
Answer: it makes a horizontal shift. for example: (x-4) means the graph moved 4 units to the RIGHT.
Step-by-step explanation: it is essentially the opposite of what you think if it's inside the parenthesis.
<h3><u><em>
Answer:</em></u></h3>
-15 > -21
<h3><u><em>step by step:</em></u></h3>
We know that 15 < 21 then -15 > -21
Answer:
4t + 29
Step-by-step explanation:
7(5 + t) - 3(t + 2)
35 + 7t - 3t - 6
4t + 35 - 6
4t + 29