Question

A quadratic function passes through the points ( − 5 , − 8 ) and ( 8 , − 8 ) . Find the equation for the line (axis) of symmetry.

Answer 1

The equation for the axis of symmetry is x=1.5.

Explanation:

It is given that a quadratic function passes through the points ( − 5 , − 8 ) and ( 8 , − 8 ) .

In the given points y-coordinates are same, i.e., -8. It means both the points lie on the horizontal line y=-8.

If a quadratic function passes through two points (a,c) and (b,c), then the equation for the axis of symmetry is

`x=(a+b)/(2)`

According to the given points a=-5, b=8 and c=-8. Put these value in the above formula.

`x=(-5+8)/(2)`

`x=(3)/(2)`

`x=1.5`

Therefore the equation for the axis of symmetry is x=1.5.