Is #y = -x - 1# a direct variation equation and if so what is the constant?

1 Answer
Oct 23, 2017

This is not a direct variation equation.

Explanation:

A direct variation requires that one variable varies at a constant rate with respect to another variable, i.e. they always have the same ratio:

#y/x =k#

Where #k# is the constant of variation. This can be rearranged as:

#y=kx#

This is similar to the equation for a line:

#y=mx+b#

where #m=k# and #b=0#. The question asks us if the following is a direct variation equation:

#y=-x-1#

which is a line with #m=-1# and #b=-1#. Since #b!=0# this is not a direct variation equation.

Please see the following link for more information and detail:
Direct Variation