Answer :

Answer: x=1

Step-by-step explanation:

Step 1: Graph using your calculator

Step 2: X=1 is where both sides of the line is equal

Answer:   x = 1

Explanation

The equation given by your teacher is of the form

y = ax^2+bx+c

In this case,

  • a = 1
  • b = -2
  • c = -8

The line of symmetry is found by this formula: h = -b/(2a)

Let's plug in the given values to find the following

h = -b/(2a)

h = -(-2)/(2*1)

h = 1

This is the x coordinate of the vertex located at (h,k).

It leads to the line of symmetry x = 1. This is the vertical mirror line splitting the parabola in equal halves. Notice how the value of c does not affect the answer. Why not? Because c only shifts the parabola up or down, which means we're moving along the same vertical line.

See the graph below. I used GeoGebra to make it, but you can use another tool like Desmos or similar.

View image jimthompson5910