Q must be positive in F.
F. r squared will be positive, because any number times itself is positive, and to get a positive number for the answer, the two numbers you multiply need to be the same sign. If r squared is positive, q must be too.
G. q does not have to be positive. If r is a negative number, then q can be negative. Say q=-2 and r=-3. -2-(-3) changes to -2+3, which equals 1.
H. Again, q can be negative if r is negative (two negative numbers multiplied together equals a positive answer.
J. q can be negative because even a negative number turns positive when squared.
Hope this helped you. :)

2) 5.625 mg will be left
Explanation:
1) Half-life = 17.5 days
initial amount of Arsenic-74 = 90 mg
To get the equation, we will use the equation of half-life:


2) we need to find the remaining amount of Arsenic-74 after 70 days
t = 70

So after 70 days, 5.625 mg will be left
Answer:
This means that we are 80% confident that the mean of the drive-through service time is between 178.0 seconds and 181.0 seconds. This conclusion was obtained after examined 576 customers. If you want a greater % of confidence you will have to lower the lower bound and increase the upper bound