Question

What is the line of symmetry for the graph of `y=-3x^2+12x-11`?

Answer 1

`x=2`

Explanation:

The line of symmetry passes through the `color(blue)"vertex"` of the parabola.

The coefficient of the `x^2" term " <0` thus parabola has a maximum at the vertex and the line of symmetry will be vertical with equation x = c where c is the x-coordinate of the vertex.

`"here " a=-3,b=12" and " c=-11`

`x_("vertex")=-b/(2a)=-12/(-6)=2`

`rArrx=2" is the line of symmetry"`

graph{(y+3x^2-12x+11)(y-1000x+2000)=0 [-10, 10, -5, 5]}