FInd the constant variation k for the direct variation 4x=-y?

Question

Not sure how to solve this with constant variation k.

Answer 1

A direct variation has the form:

 

y = kx

 

where k is the constant of proportionality.  Your equation is:

 

4x = -y

 

Multiply both sides by -1 to change the -y to y:

 

-4x = y

y = -4x

 

So k = the constant of proportionality = -4.