Answer:
Vertex at (1,-9)
Step-by-step explanation:
Expand the equation by using foil method.
You should get X^2+2x-4x-8
And then add the like terms.
X^2-2x-8
And use this formula to find the vertex.
X=b/2a
plug in the values
X=-2/2(1)
you should get x=1
Thats the one value.
For another one you have to plug in you X= (value which is 1) in the f(x) which now becomes f(1)
the answer is f(1)=-9
