Hello
This question requires us to change the subject of a formula. This can be achieved by following the order of operations in reverse. First, isolate the terms with our variable of interest, x:
ax - bx = z - y
Then, we take x out as it is being multiplied to both a and b:
x(a - b) = z - y
Dividing (a - b) on both sides, we get:
x = (z - y) / (a - b)
Thus, the answer is A
5^2 + 12^2 = c^2
25 + 144 = c^2
169 = c^2
take the square root of both sides
+ - 13 = c
3^(4x) = 3^(5 - x)
4x = 5 - x
4x + x = 5
5x = 5
x = 5/5 = 1
x = 1
At death means x= 0, so on the graph you can see that (0, 500), so 500 carbon atoms are present at death.
Plug 11,240 in for t in the equation, and you are left with N(t) = 500(1/2)^2 = 125 carbon atoms.
See the graph point (25,000, 24.298)? That means that after 25,000 years 24.298 carbon atoms will be present. So the answer is 25,000 years.