5/8 - 3/10 a. 13/40 b. 1/20 c. 1/4 d. 1/5

5/8 - 3/10

Find the common denominator:

Multiples of 8:  8, 16, 24, 32, 40 (8 x 5 = 40)

Multiples of 10: 10, 20, 30, 40  (10 x 4 = 40)

5/8 = 5*5 / 8*5 = 25/40

3/10 = 3*4 / 10 *4 = 12/40

Now you have 25/40 - 12/40

25 -12 = 13

Answer = 13/40

The answer is A.

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