Question

find the domain and range for the following equations:
y=2x-1
y=(square root of -x)+8
y=x^2-6
y=2-1/x
y=3(square root of x)+2
y=1/x+4
y=(square root of x+5)
y=(x-6)^2
y=1/(x+4)^2

Answer 1

that's a lot of equations

Answer 2

Do you know how to find domain and range?

Answer 3

sadly no. >.<

Answer 4

Okay, take y = 2 - (1/x) for example

Answer 5

what can x never equal?

Answer 6

0

Answer 7

right? xD

Answer 8

yup :)

Answer 9

so the domain is (-∞, 0) U (0,∞)

Answer 10

always?

Answer 11

yep

Answer 12

thank you so much. (:

Answer 13

wait, no...
just for that equation

Answer 14

\[y=3\sqrt{x}\]

Answer 15

what can x never equal?

Answer 16

or, what does x always have to be greater than

Answer 17

0

Answer 18

can it be 0?

Answer 19

yes?

Answer 20

yes! so, the domain is [0, ∞)

Answer 21

i dont remember the difference between the ( and [

Answer 22

[ means it includes
( it doesn't include

since we can never reach ∞, ( will always be used

Answer 23

same with -∞

Answer 24

the range is a bit complicated.

Answer 25

oh god
><

Answer 26

lets go back to: y = 2 - (1/x)

Answer 27

x can never be 0, so if we look on the graph: http://www4a.wolframalpha.com/Calculate/MSP/MSP20311hg12eagf2a7hh490000541c8369027g5cc5?MSPStoreType=image/gif&s=62&w=325.&h=151.&cdf=RangeControl

what value can y never be?

Answer 28

0

Answer 29

Hint: It's 2

Answer 30

the y value

Answer 31

WHAT this confuses me xD

Answer 32

set y = 2 and solve this for x: y = 2 - (1/x)

Answer 33

that's impossible

Answer 34

so the range will be (-∞, 2) U (2, ∞)

Answer 35

im still confused but thank you for the help. (:

Answer 36

\[y=\sqrt{x+5}\]

Answer 37

what must x be greater than?

Answer 38

0

Answer 39

in this equation x must be greater than or equal to -5 because you can't have negative square roots

Answer 40

so the domain will be [-5, ∞)

Answer 41

omg i actually get it :o

Answer 42

so, the range will be [0, ∞)

Answer 43

i just dont get how thats the range.