Select the correct answer.
How can you express (15 + 30) as a multiple of a sum of whole numbers with no common factor?
A. 2 x (7.5 + 15)
B. 3x (5 + 10)
C. 5x (3+6)
D. 15 x (1 + 2)

D. 15 x (1 + 2)

Step-by-step explanation:

answer A and B have the common factor of 5, meanwhile answer C has the common factor of 2.

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