Question

True or False? Y varies directly with x and y = -9 when x = 3. When y = 27, the value of x is 9.
True
False

Answer 1

varies directly means we are going to multiply constant and x
y=kx

now plug in x=3 and y=-9 to find the constant

Answer 2

i'm calling the constant k here

Answer 3

let me know what you get for k and i will check it

Answer 4

k = -27?

Answer 5

so we have y=kx
y is -9 and x is 3
so we have -9=k(3)
solving for k gives us k=-3

Answer 6

so we now have
y=-3x

Answer 7

@myininaya... its not directly propositional...y only varies with x...
may b a polynomial function or linear

Answer 8

what?
so anyways we have y=-3x
if y=27
then we have 27=-3x
what does imply x is?

Answer 9

"y is directly proportional to x" means the same as "y varies directly as x"

Answer 10

no... for example y=x+ 4.
y varies as x varies but it is not directly proportional

Answer 11

josh if 27=-3x, then x=-9 right? not 9
so the statement is false

Answer 12

Thanks i just figured it out xD

Answer 13

great!

Answer 14

http://www.okc.cc.ok.us/maustin/Variation/Variation-ma.htm

Answer 15

k...i got it