Suppose y varies directly as x. If y = 7 when x = 28, what is the value of x when y = 3?
we now that
A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form
y=kx
where
k is the constant of proportionality
step 1
find the value of k
k=y/x
we have
y=7, x=28
substitute
k=7/28
k=1/4
the linear equation is
y=(1/4)x
so
For y=3
substitute
3=(1/4)x
