I BET NO ONE KNOWS THIS y varies jointly as x and z. y=20 when x=2 and z=5 . Find y when x=3 and z=6

Hello!

If y varies jointly with x and z, it'll mean that x and z are being multiplied by a factor "k", to equal y.

To give you a visual, this is what I mean.

That means we'll want to find with the first point we're given:

Which means our equation is:

Now, let's plug in the and from the other point to find .

Hope this helps!