If I could have these questions answered and why.?

Question

Which of the following is a one-to-one function?

a. {(-4,-9), (-2,-8), (-4,5), (-8,-20}

b. {(-4,-9), (-2,-8), (1,1), (-2,9)}

c. {(-4,-9), (-2,-8), (1,5), (-5,-9)}

d. {(-4,-9), (-2,1), (1,-2), (-5,-5)}

2. Which of the following is true of y=f(x)= ab salute value of (x) -4

a. f is a function.

b. There is a horizontal line that crosses the graph of y=f(x) more than once.

c. f is one-to-one.

d. f has an inverse.

e. a and b

f. b and c

Answer 1

a function has a unique y for each x
one to one has a unique x for each y as well
because a. has (-4, -9) and (-4,5) it is not a function
because b. has (-2,-8) and (-2,9) is is not a function
because c has (-4,-9), (-5,-9) it is a function but not one to one
d is a one to one function
basically given a set of point...if x values repeat they need to have the same y value ....or it is not a function
and for it to be one to one if the y values repeat they need to have the same x value or it is not one to one
basically you can think every point has one and only one combo so if (-4,-9) is a point no other point can have an x as -4 or a y as -9 unless it's another
(-4,-9)

the second is the absolute value function....it is a v shaped graph so a horizontal line whoul hit is in 2 places....do a table of values and graph it and do the vertical line test....vertical line test show if a function or not....horizontal line test show is one to one or not. This passes the vertical line test but fails the horizontal line test (horizontal line touches graph in two places) So a and b work...c does not! ONly one to one functions have inverses so d doesn't fit either....so correct answer is E

Answer 2

1. To see if a function is 1:!, check if each "y" (second component) comes from exactly one "x"(first component) and each x should go to exactly one "y".
In a) you see -4 goes to -9 and also to 5.
In b), -4 and -2 both go to 9.
In c), -4 and -5 both go to 9.
d is the only one that has a different second component for each first component.
2. Think about the absolute value function, what it looks like.
If it's 1:1, a horizontal line crosses it at most once.
It has an inverse only if it's 1:1

Answer 3

2.e

Answer 4

Some ppl should do there homework
1 C & D
2 a

Answer 5

wot?

do you watch TV or read normal books?

is "tit" a metronome, a pseudonym or a word that sounds the same - spelt backwards?