Graphing & Algebraic Work...2

[nycmathguy]

Section 2.1
Question 28

I will not show my work algebraically for this problem. I will take a guess observing the Desmos graph.

1. Vertex is (-1, 30)

2. Axis of symmetry is x = -1

3. x-intercepts are x = -6, x = 4.5

The above is my guess observing the graph.
Perhaps you can prove me right or wrong by showing the algebraic work.

 

[MathLover1]

little bit off

1. Vertex is (-1/2, 30.3)

Axis of symmetry is x = -1/2

3. x-intercepts are x = -6, x = 5 (you can see on your graph that x-intercept is exactly half way between 0 and 10)

 

[nycmathguy]

little bit off

1. Vertex is (-1/2, 30.3)

Axis of symmetry is x = -1/2
View attachment 320

3. x-intercepts are x = -6, x = 5 (you can see on your graph that x-intercept is exactly half way between 0 and 10)

In the first graph, what site did you use to find the specific point as shown?

 

[MathLover1]

https://www.wolframalpha.com

it's an excellent site, I am using it for years
just be careful how you type equations

type equation in and "vertex" next to it

https://www.wolframalpha.com/input/?i=f(x)+=+-(x^2+x-30)+vertex

 

[nycmathguy]

https://www.wolframalpha.com

it's an excellent site, I am using it for years
just be careful how you type equations

type equation in and "vertex" next to it

https://www.wolframalpha.com/input/?i=f(x)+=+-(x^2+x-30)+vertex

Yes, I know about Wolfram. Do you know mathway.com?

 

[MathLover1]

Yes, I know about Wolfram. Do you know mathway.com?

yes I do, I use that one too

 

[nycmathguy]

yes I do, I use that one too

Cool.