Step-by-step explanation:
I feel like you need help figuring out what to write
For the first one say something like
These topics..... were covered in my learning check
I feel like I am pretty good with ..... topics
I feel like I need some help with ..... topics
Correct me if I'm wrong but this is what I assume your asking
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
Answer:
78.54
Step-by-step explanation:
Hope this helps!
Answer:
First one is the y is 3 times x
Second one is y is 3 more than x
Step-by-step explanation:
y is 3 times x is y = 3x
y is 3 more than x is y = x + 3