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

Question

X Y
7 11
8 13
9 15
10 17

Answer 1

If so, then y=kx
in other words, y/x = k is constant
so, does 11/7 = 13/8 ?? No.

In fact, y = 2x-3
so no, not direct variation