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!
I think it is 827!!!!!!!!!!
1000x-100m 1000x is the the staring amount and the m is the amount you take out a month
80 i would think but let another answer go first
Answer; A B and C are the correct answers also please do not follow the other links answer
Step-by-step explanation:
