If you draw out a coordinate plane you will see that they , on their Y access, are both nine witch means that they a horizontal line so all you have to do is subtract the x access witch is 3.
hope this helped
Answer:
Step-by-step explanation:
Let 
denote the half life of our substance 
to be our time, 
is mass at time t and 
as initial mass. Our half life equation can be expressed as:
from which we can obtained mass at any given time.
b. From our equation above,
we can convert our t into mins as 
We then substitute value into the equation
Hence mass after 4hrs is 
c. We can set our final mass to 
then substitute in the equation
. Substitute 
Hence time until mass is 109.83 minutes
I believe it should be c 1/4^2
When you set up 3 * (1/3), you're both multiplying and dividing by a 3. these two cancel out, and you're left with one. 3 *(1/3) is simply 1.
12 * (1/3), when you set it up, doesn't cancel out the same. multiply straight across the top (12 * 1), then divide by the bottom (3). 12/3 = 4, so 12*(1/3) is 4.
9 * (1/9) gives you the same result as the first one. the multiplied 9 and the divided 9 cancel out, and you're left with 1.
