Consider
(1) As x increases and y stays constant, z ______
(2) As y increases and x stays constant, z _____
(3) As x increases and z stays constant, y ______
Answer:
(1) As x increases and y stays constant, z increases
When y stays constant, z is directly proportional to x. So , as x increases the z also increases.
(2 ) As y increases and x stays constant, z decreases.
When x stays constant, z is inversely proportional to y. So , as y increases the z decreases.
(3) As x increases and z stays constant, y increases
(z stays constant)
So equation becomes
When z stays constant, y is directly proportional to x. So , as x increases the y also increases.