Answer:
Brien is incorrect because he skipped step 2
Step-by-step explanation:
The discount is $1,880 and the selling price is $21,620, make sure to put the dollar sign to make sure you know what the number means
The vertex is (-1, 2).
The equation of parabola:
where (h, k) is the vertex
We have h = -1 and k = 2.
Substitute:

The fist rock weighs 1/3 of a pound more
When they finish the independent reading it would be 9:40