During low tide in wrightsville, north carolina, the beachfront in some places is about 350 feet from the ocean to the homes. high tide can chance the width of a beach at a rate or -17 feet an hour. it takes 6 hours for the ocean to move from low to high tide. a. what is the change in the width of the beachfront from low to high tide? b. what is the distance from the ocean to the homes at high tide?

I also need help on this one

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