Question

Which is the quadratic variation equation for the relationship?

y varies directly with x2 and y = 72 when x = 6.

A. y = 12x


B.y = 4x2


C. y = x2 + 25


D.y = 2x2

Answer 1

We are asked to find the expression that is expressed as y varies directly with x^2.

y α x²

To convert it to equality,

y = kx²

We find the value of k by using the given values,

72 = k(6)²
k = 2

Therefore, the correct answer is option D, y=2x².