Determine if the equation

y=2/5 x = −4
represents a proportional relationship. If so, determine the constant of proportionality.

I think the constant proportionality is -0.1, but I don't know if it's a proportional relationship

2 answers

your "equation" makes no sense
But, if you mean
y = 2/5 x
then the constant is 2/5 or 0.4

If the equation has the form y = mx+b
then it is no longer a proportion. That +b gets in the way
Y = 2x/5.
y/x = 2/5.