Question

if y varies directly as x and z, and y = 6 when x = 9 and z = 3, find y when x = 7 and z = 2

Answer 1

Here is your starting equation: y=kxz
Now solve for k

Answer 2

k = 2/9, so y = 28/9

Answer 3

That's right, nice job :)

Answer 4

i have one more that i can't figure out, here it is

\[-\frac{ x^2 }{ y }=3\]

Answer 5

what are doing for this one?

Answer 6

finding the constant variation. is the constant variation 3?

Answer 7

it can't be 3.. because x is squared. right?

Answer 8

What exactly is the question?

Answer 9

it just says to find the constant variation of that equation

Answer 10

i know that y = kx and if i knew how to rewrite that equation in terms of k, i'd probably be able to figure it out.

Answer 11

There's no constant though..

Answer 12

it says -1/3, but i dont know how they got that then

Answer 13

just a guess here, but multiply y to both sides:
\[-x^{2} = 3y\]then divide each side by "3"
\[-\frac{ 1 }{ 3 } x^2 = y\]
the constant of variation would be the "-1/3" times the parabola "x^2"

Answer 14

That makes sense. Thank you!