Question

MEDALS 100%!!! HELP
The function f(x) = -x2 - 7x + 30 shows the relationship between the vertical distance of a diver from a pool's surface f(x), in feet, and the horizontal distance x, in feet, of a diver from the diving board. What is a zero of f(x) and what does it represent?

A. x = 10; the diver hits the water 10 feet away horizontally from the board
B. x = 3; the diver hits the water 3 feet away horizontally from the board
C. x = 10; the diver jumps in the pool at 10 feet per second
D. x = 3; the diver jumps in the pool at 3 feet per second

Answer 1

Do you know how to factor?

Answer 2

no :/ im not so good at math..

Answer 3

It's ok, I'll work through this slow with you

Answer 4

Do you still need help with this question?

Answer 5

yes!

Answer 6

You have to factor this out or graph it

Answer 7

So you do not know how to factor this right?

Answer 8

I say the easiest part here is to help you factor it out

Answer 9

i think you factor it yeah

Answer 10

Ok, looks like @doulikepiecauseidont has it. I don't think he would have come back if my comment hadn't reminded him, but whatever. I'll leave you to it

Answer 11

To factor expressions in the form \[\Large ax^2+bx+c \]
where a, b, c, are constants we have to go througha couple of steps

and I only stepped out @kohai cause I didn't get a response from her when I said I'll work slow I thought she left here

Answer 12

If you told me that you were going to show me something slowly, I would wait for you to start explaining, also

Answer 13

Ok, well what you have to do is

1) multiply a by c and get a number (a in this case is a negative 1 [-1], but we usually just put a - sign in front just like we never put a 1 in front of a variable we just know it's there) sow we'd get (-1) times (30) and what does that equal?

Answer 14

-1 times 30 = -30

Answer 15

OK,
2) We have to find two numbers that, when you multiply them together you get -30 but when you add them you get b (-7)

It's easier to start with the factors of 30 and then since we're trying to get -7 the bigger factor will be negative so I'll show you an example

1 and 30 are factors of 30, but remember what I told you? The bigger factor will be negative since when we add them we want a negative number and the smaller number can't be negative cause then we'd still have a positive number. Anyways we add 1+(-30) and get -29 and this doesn't work so we have to try the next factors of 30 can you tell me what they are (HINT: one of them is 2)

Answer 16

1,2,3,5,6,10,15,30

Answer 17

@doulikepiecauseidont

Answer 18

I am so sorry, I had to go, do you still need help with this question?

Answer 19

no mot any more.. thanks tho