Determine whether y varies directly with x. if so, find the constant of variation k and write the equation x 6 18 54 162 y 24 72 216 648 options a-yes, k=4; y=4x b-yes, k=3; y=3x c-yes, k=6; y=6x d-no

The constant of proportionality is usually presented as the variable k. It is usually written as:

f(x) = kx
where f(x) means a function of x. It can also be another variable, for example, y,

We test each pair to find k,

24 = 6k
k = 24/6 = 4

72 = 18k
k = 72/18 = 4

216 = 54k
k = 4

648 = 162k
k = 4

Thus, the answer is A. yes and k=4.