Question

F(x)=-11x^2 domain and range ?

Answer 1

if you plug in any number for x, will you get always get an answer back?

Answer 2

Yes

Answer 3

So -infinity ?

Answer 4

so that means your domain (number you plug in) can be any real number. so you can write that as all real numbers or as \[(-\infty,\infty)\] depending on what you have been doing in class

Answer 5

And what kind of number will you get back for any x value? consider plugging in both negative x's and positive ones. What will your y value be?

Answer 6

So (- infinity, + infinity)

Answer 7

For both domain and range ?

Answer 8

For the range? the values you get back?

Answer 9

Well domain you had correct. Any and all numbers from negative infinity to positive infinity. But what happens when you plug in a negative number for x? What is your y? positive or negative?

Answer 10

Postive

Answer 11

Positive

Answer 12

(0,infinity)

Answer 13

Hmm..
\[f(x)=-11x^2\]
\[f(x)=-11(-10)^2\]
\[f(x)=-11(100)\]
\[f(x)=-1100\]

Answer 14

Ohh I see, negative

Answer 15

So a negative answer right? You can plug in any negative number and you will get a negative answer. How about if you plug in a positive x?? Will your answer be positive or negative?

Answer 16

(-infinity , 0]

Answer 17

Yes perfect!

Answer 18

So now you have your domain:
\[(-\infty,\infty)\]
and the range:
\[(-\infty,0 ]\]

Answer 19

Make sense?

Answer 20

Yess thanks so much