Answer:
is not a function
Step-by-step explanation:
Given
![\{(-3,-1),(8,-1),(0,-5),(-9,-2)\}](https://tex.z-dn.net/?f=%5C%7B%28-3%2C-1%29%2C%288%2C-1%29%2C%280%2C-5%29%2C%28-9%2C-2%29%5C%7D)
![\{(5,9),(-3,-5),(0,4),(-9,9)\}](https://tex.z-dn.net/?f=%5C%7B%285%2C9%29%2C%28-3%2C-5%29%2C%280%2C4%29%2C%28-9%2C9%29%5C%7D)
![\{(9,0),(-5,4),(5,0),(6,3)\}](https://tex.z-dn.net/?f=%5C%7B%289%2C0%29%2C%28-5%2C4%29%2C%285%2C0%29%2C%286%2C3%29%5C%7D)
![\{(2,8),(2,1),(-9,-5),(-8,9)\}](https://tex.z-dn.net/?f=%5C%7B%282%2C8%29%2C%282%2C1%29%2C%28-9%2C-5%29%2C%28-8%2C9%29%5C%7D)
Required
Which is not a function
A function is of the form ![(x,y)](https://tex.z-dn.net/?f=%28x%2Cy%29)
Assume a function is:
![\{(x_1,y_1),(x_2,y_2),(x_3,y_3).....,(x_n,y_n)\}](https://tex.z-dn.net/?f=%5C%7B%28x_1%2Cy_1%29%2C%28x_2%2Cy_2%29%2C%28x_3%2Cy_3%29.....%2C%28x_n%2Cy_n%29%5C%7D)
In simple terms:
For an ordered pair to be regarded as a function, no x value must be repeated
Analyzing the options:
1. ![\{(-3,-1),(8,-1),(0,-5),(-9,-2)\}](https://tex.z-dn.net/?f=%5C%7B%28-3%2C-1%29%2C%288%2C-1%29%2C%280%2C-5%29%2C%28-9%2C-2%29%5C%7D)
This is a function because none of the x values (-3, 8, 0 and -9) appeared more than once
2. ![\{(5,9),(-3,-5),(0,4),(-9,9)\}](https://tex.z-dn.net/?f=%5C%7B%285%2C9%29%2C%28-3%2C-5%29%2C%280%2C4%29%2C%28-9%2C9%29%5C%7D)
This is a function because none of the x values (5, -3, 0 and -9) appeared more than once
3. ![\{(9,0),(-5,4),(5,0),(6,3)\}](https://tex.z-dn.net/?f=%5C%7B%289%2C0%29%2C%28-5%2C4%29%2C%285%2C0%29%2C%286%2C3%29%5C%7D)
This is a function because none of the x values (9, -5, 5 and 6) appeared more than once
4. ![\{(2,8),(2,1),(-9,-5),(-8,9)\}](https://tex.z-dn.net/?f=%5C%7B%282%2C8%29%2C%282%2C1%29%2C%28-9%2C-5%29%2C%28-8%2C9%29%5C%7D)
This is not a function because one of the x values (2) appeared more than once.
i.e.
and ![(2,1)](https://tex.z-dn.net/?f=%282%2C1%29)
Answer:
90.95
Step-by-step explanation:
Answer:
I don't know if this will be right but:
$20 - $2.50x
Step-by-step explanation:
You start of with 20 dollars, for each day (x), $2.50 will be taken out of your 20 each day.