Respuesta :

tramserran
A vertical parabola is: y = a(x-h)² + k
where (h,k) is the vertex and "a" is the vertical stretch/shrink.
A negative sign in front of the "a" represents a reflection over the x-axis.

y = a(x-0)² + 0
y = a(x)²
Answer: B (y = 3x²)