Remember that
In a direct variation
we have an equation of the form
y=kx
where
k is the constant of proportionality o slope of the linear equation
so
Verify each table
N 1
Find out the value of k
k=y/x
(5,1) ----> k=1/5
(7,2) ----> k=2/7
the values of k are not equal
that means
not represent a direct variation
N2
(6,3) -----> k=3/6=1/2
(12,6) -----> k=6/12=1/2
(18,9) ----> k=9/18=1/2
the values of k are the same
so
represent a direct variation
N 3
(2,10) -----> k=10/2=5
(4,20) ----> k=20/4=5
(8,40) ----> k=40/8=5
the values of k are the same
so
represent a direct variation
N 4
(4,2) ----> k=2/4=1/2
(8,4) -----> k=4/8=1/2
(12,6) ----> k=6/12=1/2
the values of k are the same
so
represent a direct variation
therefore
the first table does not represent a direct variation