The owner of a bookstore ordered 75 copies of a book and paid $1,350. The owner of another bookstore also ordered the same book and paid $1,080 for 60 copies. What is the unit price, in dollars, of the book they ordered? help

$18

Step-by-step explanation:

I did the following expressions:

1,350 / 75 = 18

1,080 / 60 = 18

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

5x+10 is the correct one

hope this