Suppose

is the number of possible combinations for a suitcase with a lock consisting of

wheels. If you added one more wheel onto the lock, there would only be 9 allowed possible digits you can use for the new wheel. This means the number of possible combinations for

wheels, or

is given recursively by the formula

starting with

(because you can start the combination with any one of the ten available digits 0 through 9).
For example, if the combination for a 3-wheel lock is 282, then a 4-wheel lock can be any one of 2820, 2821, 2823, ..., 2829 (nine possibilities depending on the second-to-last digit).
By substitution, you have

This means a lock with 55 wheels will have

possible combinations (a number with 53 digits).
The answer is the option d, which is: d) 
The explanation for this problem is shown below:
1. Smplify the denominator and rewrite the numerator in this form:

2. Multiply the denominator and the numerator by the conjugated
and simplify the expression, as following:

3. As you can see, you obtain the expression shown in the option mentioned above.
Answer:
a) The rate of change is 3.5
b) The rate of change represents the price of a single cookie. $3.5
Step-by-step explanation:
a) To determine the rate of change along the graph, select a pair on the graph as;
(2,7) and (8,28)
Rate of change, m= change in y/change in x
m=28-7/8-2 = 21/6 =7/2 = 3.5
b)
The equation of the relationship can be written as;
y=3.5 x + 0 where y is the amount collected and x is the number of cookies sold.
The slope here represents the price per cookie in $, $3.5
Answer:
if you pit the shape in a straight line it would be 180 degrees now take 180 take 130 and 100 and subtract those add that to the other 30 then take 180 divided by 60
Answer:
AB= 8/Cosine 60 degrees
Step-by-step explanation:
Cosine=Adjacent/Hypotenuse
Cosine=8/AB
AB=8/Cosine 60 degrees