Your question is not clearly stated. Do you mean the difference between 10 * 10 * x, and 7 * 7 * 7 *x ? Then the number is x = 119/243. That's about 0.48971... in decimal form.
It's confusing when you say the "difference of a number". Differences are BETWEEN two numbers. See what I mean?
Answer:

Step-by-step explanation:


You are suppose to subtract making it
X+7=13
-7=-7
______
X=6
For this case we have a function of the form:

Where,
A: it is the initial amount
b: is the growth rate
x: is the number of years
Substituting values we have:

We have a growing exponential function because the value of b is greater than 1.
Answer:
See attached image.
No, he has not watched the whole movie. The answer would be D. he only has 2/15 to watch.
Hope I helped!