When two variable quantities have a constant ratio, their relationship is called a direct variation. It is said that one variable varies directly as the other. The formula for direct variation is
y
=
k
x
, where
k
is the constant of variation.
y
=
k
x
Solve the equation for
k
, the constant of variation.
k
=
y
x
Replace
x and ywith the values.k=−42Divide −4by 2.k=−2Use the formula y=kxto substitute −2for k and −6for x.y=(−2)⋅(−6)Multiply −2by −6.y=12