Question

CHECK MY ANSWER? is the variables in the table a direct variation, an inverse variation, both, or neither?
x = 2, 5, 12, 20
y = 30, 12, 5, 3

Answer 1

i think its a direct variation

Answer 2

y=2x+2 maybe?

Answer 3

@dan815 can you help me with this when you get a chance?!

Answer 4

it cannnot be y=2x+2 because it doesnt satisfy the points, what i mean by that is the points they gave you when you sub into your equation, the left side doesnt equal the right side

Answer 5

As x gets larger, y gets smaller, right?

Answer 6

yes. but wait it is direct variation right??

Answer 7

What is your definition of "direct variation"?

Answer 8

when they both have a constant change

Answer 9

direct variation is where
y=k x
means y is propotional to x by a factor of k, if k is positive
in this case you can see that when x increases y must also increase

Answer 10

But @veganbee the "direction" of the change matters.

Answer 11

if we think of some equation like this
y=10/x
now if x is increasing y should be getting smaller because you are dividing 10 by a larger and larger number

Answer 12

^ that is called an inverse variation

Answer 13

since y= k* (1/x)

Answer 14

ohhhhhh okay i understand that

Answer 15

can you try to figure out your equation

Answer 16

if we believe it is a inverse variation
lets try to find our k in
y=k/x

Answer 17

y=60/x .....

Answer 18

ok good

Answer 19

now that makes sense right.. try subbing in the different x values and see if you are getting the corresponding y value