Answer:
Part 1) The rate of change is
Part 2) The initial value is 68
Part 3) The function rule to the linear model is 
Step-by-step explanation:
we know that
The linear equation in slope intercept form is equal to

where
m is the slope or unit rate
b is the y-intercept or initial value
step 1
Find the slope
take two points from the table
(0,68) and (15,85)
The formula to calculate the slope between two points is equal to
substitute the values
In a linear function , the slope is the same that the rate of change
therefore
The rate of change is
step 2
Find the y-intercept
we know that
The y-intercept is the value of y when the value of x is equal to zero
Looking at the table
For x=0, y=68
therefore
The y-intercept is
The y-intercept is also called the initial value
therefore
The initial value is 68
step 3
Determine the function rule to the linear model

we have
substitute

A and d seem correct to me.
b and c are definitely wrong.
I'm assuming the problem is nine to the third power divided by nine to the ninth power, so the answer would be 0.000001882. Fraction form would be 1/531441.
Sorry about the first answer, I read the problem wrong.
Yep!
Weighing #1: Start off by splitting the pile of 12 coins evenly into two piles, 6 in each pile. Put one pile on each side of the balance. The side that is weighed down has the fake coin it in. Ignore the other 6 coins.
Weighing #2: Now you have 6 coins left. Split the pile evenly again, 3 in each pile. Repeat the same process and put each pile on one side of the balance. The side that is weighed down has your fake coin in it. Ignore the other 3 coins.
Weighing #3: You have 3 coins left. Take two coins, whichever two you like, and weigh them. If they weigh the same, then the one you didn't weigh is the fake one. If one is heavier, then that heavier one is your fake coin.