Question

Could someone explain to me how to graph quadratics, please?

Answer 1

By using completing square,
we can obtain the vertex and the y-intercept of an quadratic equation,
then plot it !

Answer 2

isn't plotting of points and intercept method applicable?

Answer 3

No idea. I have to answer this:

Which of the following is the vertex of the quadratic equation y = –4(x – 6)2 + 2?

Answer 4

(6, 2)
(–6, –2)
(6, –2)
(–6, 2)

Answer 5

Where did you get 27??

Answer 6

nonono i'm sorry
the above is wrong , (6,27) is the vertex

Answer 7

y-intercept is obtained by substituting x=0

Answer 8

Right but the answers i can choose from are above. Those aren't in it.

Answer 9

you should use an uparrow to show the square:
y= -4(x-6)^2 +2

the vertex is x=6. replace 6 in the equation to get y.

Answer 10

Ohhhh okay. Thank you! Can you stick around so i could see if i got it right? Lol

Answer 11

I think they want you to remember that the vertex is easy to find when the equation is in that form. (6,2)

Answer 12

Oh okay well thank you!

Answer 13

Another one:
y= 2(x-1)^2+3

the vertex is where (x-1) is zero, so it's when x=1.
And when x=1, then 2(x-1)^2 is 0, so y=3
vertex is (1,3)

Answer 14

Which of the following is the equation of the axis of symmetry of the quadratic equation y = 2(x – 4)^2 + 7? << So for this one, x=-4?

Answer 15

-4-4= -8

Answer 16

you want (x-4)= 0 (not -8)

Answer 17

I'm so confused lol. I'm lost.

Answer 18

Look at the (x-4) part. What x makes it 0?

Answer 19

What x?

Answer 20

equation y = 2(x – 4)^2 + 7? << So for this one, x=-4?
^
| this x

Answer 21

Yeah?

Answer 22

if x=4 what is (x-4)?
replace x with 4 to get (4-4)=0
so your answer is x=4 (not x= -4)

Answer 23

Ohhh gotcha. Okay so then what's next? you substitute 4 for x?

Answer 24

If you wanted to find the y value of the vertex.
but for the axis of symmetry, you have the answer. It's x=4
(which is a vertical line)

Answer 25

Ohhh okay. Thank you (: You're a big help

Answer 26

Only if you now understand how to do the problem....

Answer 27

I do.. Well those two forms of questions. I dont get this one..
What is the domain and range of the quadratic equation y = (x – 5)2 + 10?

Answer 28

So yeah..

Answer 29

you mean
y = (x – 5)^2 + 10

the domain are all the x values. Generally it would be all numbers, except if you ended up dividing by 0 (a big no-no)
You are not dividing here.
range is all the y values that you can get from the equation.

Answer 30

Alright well in the answers, they have \[\ge or \le\]

Answer 31

First, answer what is the domain?

Answer 32

5?