Respuesta :

JcAlmighty
The answer is C. y = 4x^2

y varies directly with x2 can be expressed as:
y = k*x²

When x = 3, they y = 36. And you just need to replace it in the equation from above:
36 = k*3²
36 = k*9
⇒ k =36/9 = 4

So, the related equation is
y = 4x²