Answer:
C
Step-by-step explanation:
A function cannot have multiple y values for one x value.
Option A lists the y values of -8 and 10 for the x value of -4. Therefore this is not a function.
Option B lists 0, 5, 10, AND 15 all for -1. This can't be a function either.
Option C does not have two of the same x values for different results. Although both 0 and 9 give you the answer of 1 for the y value, this is perfectly okay in a function. This is your answer.
The second choice! I hope my math is right!
Answer:

Step-by-step explanation:
Given


Required
Determine the percentage of the tip
First, we calculate the amount paid



The percentage of the tip is then calculated using:





Answer:
thats not even understandable
Answer: r = 7
Step-by-step explanation:
Subtract 12 from both sides to isolate the r variable. You have -42 = -6r. Divide both sides by -6 to get r by itself and you get r = 7. Verify by substituting 7 as the r value and solving the equation.