Question

Which is the quadratic variation equation for the relationship?

y varies directly with x2 and y = 36 when x = 3.

A.
y = x2 + 25

B.
y = 4x2

C.
y = x2

D.
y = 12x

Answer 1

`y=kx^2 \\ \\ y=36 \hbox{ when } x=3 \\ 36=k * 3^2 \\ 36=k * 9 \\ k=4 \\ \\ \boxed{y=4x^2} \Leftarrow \hbox{answer B}`