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 
1) 3/5=9/x (cross multiply<span>)
3x=5(9)
3x=45
x=15
2) </span>2/4=x/12 (cross multiply<span>)
</span> 2(12)=4x
24=4x
<span> 6=x
</span>3) 10/x=5/9 (cross multiply<span>)
10(9)=5x
90=5x
18=x
</span>
4) 5/6=x/18
5(18)=6x
90=6x
x=15
Okay. So the equation is 4x² - 16. We're talking about moving 7 units to the right and 3 units down. That formula would be h(x) = 4(x - 7)² - 19, because you would add -3 to the -16 units to get -19, and you would put the parenthesis around x and the 7 in order for it to move right. Keep in mind that parenthesis around x and a term means that we move either left or right, which didn't occur in the original equation. -16 is the amount of units down and adding -3 to it makes it -19. The answer is A.