Answer:
16,000 starfish
Step-by-step explanation:
year 0: 1000
year 1: 2000
year 2: 4000
year 3: 8000
year 4: 16000
After the first three days, the sample size will be half of the initial; therefore, 400g/2= 200g. However, it is asking how long will it take to decay to 100g, so we will take 200g/2= 100g, which will take another three days. It will take 2 half-lives, which will encompass 6 days.
2a+b=-7
5a+b=-13
b=-2a-7
5a-2a-7=-13
3a=-6
a=-2=first number
2(-2)+b=-7
-4+b+-7
b=-3=second
Answer:

Step-by-step explanation:
Lets solve the first half.

Second one:

Now compare.....Not the same right??
So your answer is: 
Hope this helps :)
Answer:
1) solution is y = -7
2.) DNE
3.) Solution is y = -2
Step-by-step explanation:
1.) 2+3 = y + 12
Add the LHS and make y the subject of formula
5 = y + 12
Y = 5 - 12
Y = - 7
The solution of the equation is - 7
2.) 2 + 13 = 1 +8
Since there is no unknown variable and the sum of the numbers in the left hand side ( LHS ) is not equal to the sum of the numbers in the right hand side ( RHS ), it will be concluded that there is no solution in the equation.
3.) y - 7 = 2 - 11
Sum the RHS and make y the subject of formula
Y - 7 = -9
Y = -9 + 7
Y = -2
The solution of the equation is -2