Answer:

Step-by-step explanation:
we have

This is the equation of a vertical parabola open upward
The vertex is a minimum
The equation of a vertical parabola in vertex form is equal to

where
(h,k) is the vertex
Convert the given function to vertex form
Factor the leading coefficient

Complete the square


Rewrite as perfect squares
------> equation in vertex form
The vertex is the point (2,6)
Answer:
4 seconds
Step-by-step explanation:
using the vertex formula of a quadratic,
, where (h,k) is the vertex
h is height and t is time in seconds
the vertex (maximum height) of the dolphin is (h,k) or (0.5, 2)
Height of 1/2
time of 2 seconds
it will take 2 additional seconds to reach the water again.
this can also be solved using quadratic equation, but since it was already set up in vertex form, i'd use that.
3(x + 3y + 2x − y) = 3(3x + 2y)
= 9x + 6y
See if any of these match an answer option.