Question

Glven the function f(3) = x2 - 4x - 5,

Answer 1

So to find the zeros you need to break down the problem into two sets of parenthesis. So you need to figure out what two numbers multiply to get -5 and when added give you -4. Start by writing the factors of 5.
1,5 so now you have the two numbers, since the answer has to be negative we need to figure out which one needs to be negative so that when we add them we get -4
-1+5=4
1+-5= -4
Now that we have that we can see our factors are 1 and -5 so we write it like this
(X+1)(x-5)
To find our zeros we take each parenthesis and set them equal to zero
X+1=0
X-5=0
Now solve
X=-1
X=5
These two numbers are where the parabola will touch the x axis. Now you need to graph the point they give you. That’s I’ll be the center of the parabola. Next put a dot on (-1,0) and (5,0). Now to figure out which way to draw the parabola you just look at the sign in front of the x^2 on the original equation. Since there’s no negative sign your parabola will open upwards. Hope this helps