Is x+y=0 a direct variation?

1 Answer
Feb 22, 2018

#color(blue)(x+y=0)# is a direct variation.

Explanation:

Notice that #color(blue)(x+y=0)#
can be written as #color(green)(y=color(red)(""(-1))x)#
the standard form for a direct variation with constant of variation #color(red)(""(-1))#
or
we could notice that #(x,y)=(0,0)# is a valid solution and that
if #(x,y)=(a,b)# is a solution then so is #(x,y)=(k * a, k * b)#