Axis of Symmetry

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3:05-3:50

The vertical line that splits the parabola down the middle.

Since with the factored form equation you are given two X intercepts, you can find out the Axis of Symmetry by finding the average of the two. By doing so, you get the middle of the x intercept.

With this, the general formula is

If y= a(x-s)(x-t) than: x=s+t

2

Example

y=(x-8)(x-2)

x=8+2

2

x=5

Question

What is the Axis of Symmetry of the factored equation y=(x-17)(x-2)

Solution

y=(x-17)(x-2)

x=17+2

2

x=9.5