1a. It is because each x only has 1 y and it has an equation
1b. It is not a function because each x has more than 1 y.
1c. It is not a function because there can be no equation written for this graph.
Answer:

Step-by-step explanation:
There are

different ways to select the four numbers between 1 and 42. Only one of this ways is correct (successful to win).
There are 30 different ways select the single number between 1 and 30. Only one of them is correct.
The probability of winning the jackpot is

Here we get the statement:
"sec^-1(0.5) is undefined"
And we want to see if this is true or false, so let's use the properties that we know to find that this is false.
Remember that the sec function is defined as:

Then we will have:

Then is really trivial to see that:

Then we can conclude that the function is not undefined at 0.5, so the statement is false.
Below you can see the graph of the given function, and you will see that it is never undefined.
If you want to learn more, you can read:
brainly.com/question/16453813
Answer:
5r-2
Step-by-step explanation:
The measure of each exterior angle = the measure of each central angle.
each angle = 360 / 16 = 22.5