What is the y-value of the vertex of the function f(x)=-(x+3)(x-14)?

If we expand the product, we have

The x-coordinate of the vertex is given by

Plug this value in the equation to find the correspondant y-value:

use an equation of ratios to determine the amount of gas needed to fill the tank.

    0.2             0.8

  =    

288.75             x

                                                              231 gal

so, 0.2x = (0.8)(288.75 gal), and x = = 1155 gal.

                                                                0.2

it would take 1155 gal. to fill the tank.

the cost would be

1155 gal         $3

* = $3465   (answer)

      1           1 gal

hope this you