The answer is the second option you are correct !
Every function is a rule which tells you how to associate inputs and outputs. The input, also known as independent variable, is often indicated with the letter
, while the output, also known as dependent variable, is often indicated with the letter
.
With this notation, we write
, read "y is a function of x", in the sense that the value of the variable y depends on the value of the variable x, and f is the function that tells you how y depends on x.
In your example, you have
, which means "subtract four times the input (4x) from 2"
So, it doesn't matter which input you chose (i.e. the value for x), because you will always have to behave this way:
- Pick an input value, x
- Multiply it by four to get 4x
- Subtract this number from 2: 2-4x
Here are some examples of explicit calculations: if I choose
and input, the workflow will be
- Pick an input value, 2
- Multiply it by four to get 8
- Subtract this number from 2: 2-8=-6
So, if the input is 2, the output is -6
Similarly, if we choose
as input, we have:
- Pick an input value, 0
- Multiply it by four to get 0
- Subtract this number from 2: 2-0=2
So, if the input is 0, the output is 2. And so on: for every possible value for x you have the correspondant value for y, with the function f telling you how to associate one with the other.
Look at the picture.
1)|AM| = |MB| = x
|AN| = |NC| = y
|BC| = 2y - 2x = 2(y - x)
|MN| = y - x
Therefore |BC| = 2|MN|
2)|AM| = |MB| = x
|AN| = |NC| = y
|BC| = 2y - 2x = 2(y - x)
|MN| = y - x
Therefore |BC| = 2|MN|
Answer:

Step-by-step explanation:
GIVEN: two two-letter passwords can be formed from the letters A, B, C, D, E, F, G and H.
TO FIND: How many different two two-letter passwords can be formed if no repetition of letters is allowed.
SOLUTION:
Total number of different letters 
for two two-letter passwords
different are required.
Number of ways of selecting
different letters from
letters


Hence there are
different two-letter passwords can be formed using
letters.
Answer: 7
Step-by-step explanation:
if Martha jarred 6 liters of jam in 2 days,
she will jarred 3 litters of jam in one day
for 21 litters she will need 7 days
21/3=7