Question

@directrix

Answer 1

If the axis of symmetry is x = -1, then the x coordinate of the vertex of the parabola is -1.

If the height of the parabola, then the y coordinate of the vertex is 6.

That gives the vertex as (-1, 6)

Answer 2

That eliminates two of the options.

Answer 3

So, it wouldn't be option D or C, correct?

Answer 4

In the options, replace x by -1 and if y does not crank out to be 6, then discard that option.

Answer 5

Would that make it option A? Or did I do something wrong?

Answer 6

I don't see any work for checking option A.

Are you saying you think option A is the correct answer?

Answer 7

I think it is option A or C because I see the negative sign next to 1 (because we have -1 as one of the points) and I wasn't sure if it was -0.56 or -2.5

Answer 8

We still have to get the parabola that passes through the point (-2, 1).

Answer 9

Okay, let's check option A.

Answer 10

How would we do that?

Answer 11

Isn't there a formula that goes something like

\[t=-b/(2a)\]

Answer 12

Test option A
--------------

y = -.56(x-1)^2 + 6

First test: Check to see if the vertex coordinates work.

Vertex (-1, 6)

Does 6 = -.56(-1-1)^2 + 6

No, so Option A is out.

Answer 13

Then that leaves me with option C? So, would that make option C correct?

Answer 14

Check Option B

y = -.5(x+1)^2 + 6

Test vertex (-1,6)

Does 6 = -.5(-1 + 1)^2 + 6

6 = -.5 *0 + 6
6 = 6

So, yes, Option B is still in the running to be the answer.

Second test coming up for Option B.

Answer 15

So, we have B, C, and D.

Answer 16

Option A and B are out. So we have C and D left.

Answer 17

Right.

Option C passed the vertex test.

Check it for the point test.

Is (-2, 1) a point on the parabola: y = -2.5(x-1)^2 + 6

Does

1 = -2.5( -2 -1)^2 + 6 ?

1 = -2.5 * (-3)^2 + 6

1 = -2.5 * 9 + 6

1 = -16.5 No

Something is not right with my calculations or whatever.

Do you see any errors?

Answer 18

So, option C is correct?

Answer 19

So, is it option C?

Answer 20

Hold on.

Answer 21

Okay.

Answer 22

I am graphing the options. Here is option A.

Look and see if it has vertex (-1, 6) AND also passes through the point (-2, 1).

Post what you think while I graph the second one, okay?

Answer 23

Whoa! I think I misread option B.

Is that a -5 or -.5 in the problem?

Answer 24

I don't think it's option A because it doesn't pass through the vertex (-1,6) or (-2,1).

Answer 25

-5 (no decimal)

Answer 26

I am returning to option B with the correct equation.

Is (-2, 1) a point on the parabola: y = -.5(x+1)^2 + 6

Does 1 = -5( -2 +1)^2 + 6

Does 1 = -5 * 1 + 6

1 = 1 Option B is the correct option. ***

Answer 27

So, I should choose option B, correct?

Answer 28

Let me graph it first. Sorry about misreading the problem.

Answer 29

No problem. And alright.

Answer 30

This looks like the winner.

Answer 31

It does to me too, because looking at it I see that the vertex is at (-1,6) that is where the top of the line/circle is and it goes through the point (-2,1).

Answer 32

I checked again and I am going with Option B.

Answer 33

Wow. What a hassle misreading the problem causes. No worries because we kept on working.

Answer 34

>>So, I should choose option B, correct?

Correct.