Question

if y varies jointly as x and z and y=18 when x=2 and z=3 ,, find y when x=5 and z=6

Answer 1

please help

Answer 2

Varies jointly means it varies directly with two or more variables. So write y = kxz.

Answer 3

Then substitute the given values for y, x, and z and find k

Answer 4

When you wrote x = 2 and x = 3 did you really mean x = 2 and y = 3?

Answer 5

no x=2 and z=3

Answer 6

18=k(2)(3)

Answer 7

So what is k?

Answer 8

would it be 36???
y=k/x
18=k/2
18=36/2
?????

Answer 9

Did you see the equation I wrote: y = kxz?

Answer 10

That is the joint variation. y varies jointly with x and z

Answer 11

im still not understandingg

Answer 12

There are 3 basic types of variation.
(1) y varies directly as x and the equation is y = kx
(2) y varies inversely (or indirectly) as x and the equation is y = k/x
(3) y varies jointly as x and z and the equation is y = kxz

Which one of those is this problem you posted?

Answer 13

Is it direct, inverse, or joint?

Answer 14

i posted jointly but when i do jointly i have to find k and the way im doing it is the way i showed uu and i dont think when im doing jointly im doing it right

Answer 15

Everything you just said is correct. So since it is joint variation, why don't you use the joint variation equation?