Question

Explain the procedure (but don't create the graph) for graphing the quadratic function in factored form f(x) = (x - 2)(x + 4) using pencil and paper. Explain the entire process. pleaaassseee help mee.

Answer 1

Answer:  You will need to find the x-intercepts and the vertex

Step-by-step explanation: Use the information in the factors and some formulae.

The x- intercepts are the points where the parabola crosses the x-axis. The x-axis is where y = 0

Set each factor equal to 0 and solve:

x-2=0, so x = +2 and x +4 = 0, so x = -4    (you would plot these if creating the graph)

To find the vertex you need the Vertex Formula: x = -b/2a

b is the coefficient of the x term in the middle of the quadratic equation; you can just do the O and I parts of FOIL to get b:  -2x + 4x = 2x  You know a = 1 because x²  will have the implied (missing)(1).

Put the numbers in the Formula: x = -b/2a   x = -(2)/2(1)  -2/2 = -1  

-1 is the "x-value" of the vertex.  

The y value is the 'c' in the quadratic formula. You get that from the  L part of FOIL   -2 × 4 = -8 .

So, your coordinates for the vertex:  ( -1, -8 )

If you were creating a graph, you would plot that point, then draw the parabola starting there and through the x-intercepts.