Write the decimal as a fraction or mixed number in simplest form: -0.8a.-2/25b.-4/5c.4/5d. -1 1/4 what is the correct answer?

C. 4/5

Step-by-step explanation:

step 1: convert the decimal to a fraction which is -8/10

step 2: find the greatest common factor of each which is -2

step 3: divide -8/-2 = +4

step 4: divide -10/-2 = +5

step 5: write the simplified fraction

(the plus sign in front of the two numbers means that they are positive)

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