How do you determine whether y varies directly with x and if so, how do you find the constant of variation k for 5y=5x+10?

1 Answer
Apr 9, 2015

5y=5x+10
could be simplified as
y=x2

According to
http://www.merriam-webster.com/dictionary/direct%20variation
Definition of DIRECT VARIATION
: mathematical relationship between two variables that can be expressed by an equation in which one variable is equal to a constant times the other

from which it follows that the given equation is not a direct variation (i.e. y does not vary directly with x).

The equation of a line parallel to this which would be a direct variation would be
y=x
or y=(1)x
and for this equation the constant of variation would be (1)