Find The Variation Constant And An Equation Of Variation Where Y Varies Directly As X And Y=36 When X = 9?

If y varies directly as x, there exists some variation constant k such that
y = k*x
Dividing both sides by x, we have an expression for k.
Y/x = k
You have been given values of y and x, so this is easily computed.
36/9 = k = 4

The variation constant is 4.