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).
Lol i learned this last chapter. ok here is one 2x + 3 < 5
Answer:
The width of the window should be 
and the height of the window should be 
Step-by-step explanation:
we know that
The circumference of a semicircle (window) is equal to
we have that
substitute and solve for r
so
the width of the window is equal to the diameter of the semicircle
so
The width of the window should be 
and the height of the window should be
- 4 1/5 = -21/5 = -42/10
-13 1/10 = -131/10
-42/10 - -131/10=
-42/10 + 131/10 = 89/10 = 8 9/10
answer is A
Answer:
(x - 5)(x + 3)
Step-by-step explanation:
to solve x² - 2x = 15, we need to get all the terms on one side so we can solve the quadratic equation using factoring. to do this, we subtract 15 from both sides
x² - 2x = 15
- 15 -15
x² - 2x - 15 = 0
now we can factor. we need 2 numbers that when multiplied together give us -15, and when those 2 numbers are added together we get -2
because we have a -15, we can assume that one number must be negative and the other positive, as a negative times a postive is a negative.
we can use 3 and -5 as factors and test it out. we put x in front because we have an x²
(x - 5)(x + 3) < we can FOIL to check to see if this is correct. its not mandatory to check but when you arent sure of the answer you can FOIL it out
FOIL stands for: First, Outside, Inside, and Last terms
F: (x - 5)(x + 3) = x²
O: (x - 5)(x + 3) = -3x
I: (x - 5)(x + 3) = 5x
L: (x - 5)(x + 3) = -15
x² + 3x - 5x - 15 < subtract 3x from 5x
x² - 2x - 15
this checks out, so our answer is (x - 5)(x + 3)
