Identify which of the following representations are functions. If not a function state how you would fix it to make it a function. 1. D = (4, -1), (3, -6), (2, -1), (1, 2), (0, 4), (2, 5)

2. The number of calories you have burned since midnight at any time of the day.

1. Not a function: the x input is repeated twice.

2.

if the eqn of the parabola is f(x) = (x-4)(x+2), we need to mult. this out to find the coordinates of the vertex.

then f(x) = x^2 + 2x - 4x - 8, and f(x) = x^2 - 2x - 8.

one way in which you can find the vertex is to calculate x = -b / (2a).   here, that comes to

        )

x = = 1.   f(1) = 1^2 - 2(1) - 8 = - 9.   vertex is at (1, -9).

        2(1) 

find another point on the curve:   let x=0, for which y=-8.   then (0, -8) is on the curve.   plot the vertex and this point and draw a smooth parabola thru both.

hope this

option: d is correct

step-by-step explanation: