Answer:
a) Two half lives, b) 
Step-by-step explanation:
a) The polonium-210 has a half life of 138.4 days. Therefore, 1.994 half lives have past.
b) Mass decay is described by the following exponential model:

The time constant for the isotope is:


The mass of the isotope after 276 days is:


Answer:
B but am not sure tho it's probably A
Answer:
64
Step-by-step explanation:
Start with the second expression. That factors easily into (8x-3)(8x+3).
Since 64x^2 + 48x + 9 has no negative signs, I'd bet that the common factor is (8x+3). Divide <span>64x^2 + 48x + 9 by that to verify.
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