Juan is shopping for school supplies. He bought a pencil case for $5.00, but now he needs pencils to go inside it. Each box of pencils $3.00. Let t represent the total cost, and b represent
each box of pencils. Determine the dependent and independent variables.

T is dependent B is independent

Step-by-step explanation:

Total cost is changed by how many pencils you buy

The price of each box of pencils does not change

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