Question

Determine whether y varies directly with x. If so, find the constant of variation k and write the equation.

x- 4, 7, 10, 13
y- 6.4, 11.2, 16, 20.8

Answer 1

Determine y/x for all the given values
if all results are the same,then y varies directly with x
your k is the result of the division and y-kx

Answer 2

divide all y's by x's.
I'll show you the first two: 6.4 divided by 4 = 1.6 and 11.2 divided by 7 = 1.6
If the rest equal 1.6 then y does varies with x.