Barb went to grottos pizza and ordered 7 large pizzas her total bill was $49

x=7 and y=$49

Step-by-step explanation:

Let x be the # of pizzas ordered and k be the unit cost (per pizza).

Then we have y = kx = ($7/pizza)x.  In other words, k = $7/pizza, x = 7 and y = $49.  This is the third answer choice.

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