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

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Answer 1 · 2017-10-23T20:43:28

This is not a direct variation equation.

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