The formula is a permutation in which n represents the sample points in the set, while r represents the number of sample points in each permutation.
The correct answer is A.
You have direct variation if x and y are modeled by the equation

In this case, m is the constant of proportionality. So, if the constant has to be 2, the equation becomes

A side note: Actually, option C has a constant of proportionality of two as well, except the roles of x and y are interchanged. I chose option A because usually you want the y = mx form, but the names of the variables are obviously meaningless.
R in this equation refers to the radius
Answer:
A) -2/5
Step-by-step explanation:
Note that for a slope, the slope of the line is found by using the equation:
slope = (rise/run).
In this case, find two points. For example, i will use:
(0, 2) & (5, 0). (x = 0, y = 2) ; (x = 5, y = 0)
Note that "rise" = y, and "run" = x. Plug in the corresponding numbers for the corresponding points.
(2 - 0)/(0 - 5) = slope
Simplify
(2)/(-5) = slope
-(2/5) is your answer.
Note that it does not matter where the negative sign is placed.
~
Answer:
x = 8
Step-by-step explanation:
Step 1: Write an equation
2x - 9 = 7
Step 2: Use the Addition Property of Equality
2x = 16
Step 3: Use the Division Property of Equality
x = 8