Answer:
x = k/(y+z)
Step-by-step explanation:
We need to write a general formula to describe the variation: x varies jointly with the inverse of the sum of y and z
it can be written as
x ∝ 1/(y+z)
or can be written as
x = k/(y+z)
where k is the constant of variation introduced when we remove the ∝ sign.
