I think your answer is correct!
Answer:

Step-by-step explanation:
The half life is the amount of time it takes a substance to decay to half of its original amount.
Since the radioactive substance has a half life of 1000 years, there will be half of it left after 1000 years.
So, the fraction that will be left after 1000 years is 
Answer:
x = 6
Step-by-step explanation:
44 + 3x = 5x + 2x + 20 transfer like terms to the same side of the equation with the opposite sign:
44 - 20 = 5x + 2x - 3x add/subtract like terms
24 = 4x divide both side by 4
6 = x
4x^2 + 8x + 12
Equivalent forms: x^2 + 2x + 3 and 8x^2 + 16x + 24.
The first equivalent form was created by dividing each term by 2, and the second equivalent form was created by multiplying each term by 2.