Answer:
x=-2
y= 8
Step-by-step explanation:
Given data
10x – 2y = -36-----------1
7x – 2y = -30--------------2
-Subtract to eliminate y
3x-0= -6
3x= -6
x= -6/3
x= -2
Put x= -2 in
7(-2)– 2y = -30
-14-2y=-30
-14+30=2y
16=2y
y= 16/2
y= 8
Notice this is a geometric progression since each number multiplied by some factor equals the next number in the sequence, in this case,

Then by applying the formula for sum to infinity of a geometric progression,
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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Answer:
Step-by-step explanation:
21. (24)(2)/6+4=48
=48/6+4
=8+4
=12