I REALLY need your guys math help - ALG 2 - Quadratics

chill_davis

chill_davis

Active member
Uh so basically I'm shitting the bed in ALG 2 and we got a take home quiz and I have no idea what the fuck I'm doing.

So I was given the function: f(x)= =3x^2-9x+2

(the ^2 is exponent)

and I need to find:

The y intercept

The axis of symmetry

The x-Coordinate of the vertex

Make a table of values that includes the vertex

Find the maximum and minimum values

and sketch the graph.

In all seriousness anyone who can answer all this correctly for me will get $5 in their paypal.

Post your reponses here

First come first serve.

Thanks NS
 
I tried but it gives me all this bull. Negatives and shit and doesn't seem right, I've got a D and I need this fucking grade I just want to make sure it's right.
 
well to find the y intercept, you need to set the x's equal to 0. so the y intercept is 2.

 
(Ill do it!!! here:

f(x)= =3x^2-9x+2

y-intercept = (0, 2)

The axis of symmetry

= x = 1.5

Vertex

= (1.5, -4.75)

Make a table of values that includes the vertex

x y

-1 14

0 2

1 -4

2 -4

1.5 -4.75

3 2

4 14

Find the maximum and minimum values

^(infinity = max and min?)

and sketch the graph.

(Use the table to graph it)

My paypal is kpazar@comcast.net

:D

 
Alright im like 2 chapters ahead of you.

Minimum value - use your calculator

To find the vertex use this -

(-b)/(2a)

That will give you the x value of the vertex, and then you plug in that in the equation

Axis of symmetry is the x value you just found

And since its quadratic and since a is positive its going to have a minimum.

Im blanking on the y intercept though, sorry man
 
critical points exist when the derivative of the function equals 0.

f(x)=3x^2-9x+2

f ' (x)= 9x-9

9x-9=0

x=1 is a critical point. now the problem should have an interval. evaluate the function at each point including the critical point. the highest is the max, lowest the min.

y intercept, using y=mx+b

find the slope using two points, for example (0,2) and (1,-4). slope= change of y/ change of x (5/6 in this case). now use the point (0,2) and m=5/6 to find b (the y intercept). 2= (5/6)*0 + b. b=2.

that is all for now

 
so opposite of -9 is 9 divided by 2 times 3 gives you 9/6 as your x value for the vertex. then you plug it in, and you get 3(9/6)^2-9(9/6)+2. i dont have a calculator at hand, but thats your y value.
 
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