3a + b = 54...when b = 9
3a + 9 = 54
3a = 54 - 9
3a = 45
a = 45/3
a = 15 <===
She cuts off 21 cm. this leaves 63cm. cut into 6 equal pieces gives 10.5 cm pcs
The mass of radioactive material remaining after 50 years would be 48.79 kilograms
<h3>How to determine the amount</h3>
It is important to note that half - life is the time it takes for the amount of a substance to reduce by half its original size.
Given the radioactive decay formula as
m(t)=120e−0.018t
Where
t= 50 years
m(t) is the remaining amount
Substitute the value of t


Find the exponential value
m(t) = 48.788399
m(t) = 48.79 kilograms to 2 decimal places
Thus, the mass of radioactive material remaining after 50 years would be 48.79 kilograms
Learn more about half-life here:
brainly.com/question/26148784
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The absolute value of an given number is always positive. So, when adding two to any positive number will always be greater than the number by itself.