Answer:
2
Step-by-step explanation:
5-3=2 it's simple really
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!
Linear functions are graphs with a straight line. With 1 independent and 1 dependent variable