Question

What is the vertex for the graph of y = −3x^2 + 18x − 13?

Answer 1

I'm pretty sure the formula for this is ax^2 + bx + c = 0.

Answer 2

And I got, -3x^2 + 18x - 13.

Answer 3

I just don't know what to do from there.

Answer 4

@Chris9k What would I do next, do you know?

Answer 5

I just realized I got the answer as the problem.. so I messed up some where.

Answer 6

Unless I don't use this formula..

Answer 7

First, realize what kind of graph it is. It is a upside down parabola. Which means you are trying to find that max point on the graph. You can always graph the equation in a calculator. Or take the derivative and set it equal to 0. Derivative will be -6x+18...set that equal to zero.... -6x+18=0; x = 3 Plug x = 3 back into the original equation to find y and that point (x,y) is your vertex.

Answer 8

(-3,14) is what you will end up with..

Answer 9

Well, I didn't read all of that. I believe the U or upside down U would be opening downward, because the square is negative.

Answer 10

Yes, that is true.

Answer 11

But you messed up somewhere.

Answer 12

The only options I have to choose from are these. (−3, −40)

(−3, −94)

(3, 23)

(3, 14)

Answer 13

Sorry...didn't mean to put a -3...finger slipped...(3,14)

Answer 14

Lol.

Answer 15

I even wrote before that that x =3 lol oh well..you got it.

Answer 16

Well, now it's not negative. So the U would be opening up upward.

Answer 17

So confusing.

Answer 18

U is still downward....look at your original equation..the squared term is -3x^2...which tells you it opens downward....it just starts from (3,14) and goes down.

Answer 19

. Geometry is going to suck man.. :[

Answer 20

It's not too bad. Just take good notes in class and keep up with the homework.

Answer 21

I do schooling online. I have to teach my self or be taught by someone on this site. :/

Answer 22

Tough. Read the book...a lot. Good luck.

Answer 23

Thanks.