Step-by-step explanation:
Since
varies directly as
we can write the relation as

where k is the constant of proportionality.
a) To solve for the k, we substitute the given values:


b) The equation relation x and y can be written as

c) When y = 9,

Multply both equations by 2 leaving
x + 2y = 8
x - 2y = -2
Add the equations giving
2x = 6
x = 3
Substitute 3 in the top equation
3 + 2y = 8
2y = -5
y = -2.5
Answer:
8
5
-1
-4
Step-by-step explanation:
What are you supposed to be doing