How do you graph the quadratic function and identify the vertex and axis of symmetry for y=-1/6x^2+x-3?

1 Answer
Feb 27, 2017

See explanation

Explanation:

As the coefficient of x^2 is negative the graph is of general shape nn

There is no stipulation in the question about how you are to determine the information so I chose the following method

color(blue)("Determine the y-intercept")

color(green)("y-intercept is at the same value as the constant ie "y=-3)

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color(blue)("Determine the vertex")

Write as -1/6(x^2-6x)-3

color(green)(x_("vertex")=(-1/2)xx(-6) = +3)

Substitute x=3 and we have

color(green)(y_("vertex") =-1/6( 3^2-(6xx3))-3" "=" "-1.5)

color(green)("Vertex "->(x,y)=(3,-3/2)
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color(blue)("Determine the x-intercepts")

As the graph is of form nn and y_("vertex")=-1.5

The curve doe NOT cross the x-axis.

So there is no solution to " "-1/6x^2+x-3=0
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color(blue)("Determine the axis of symmetry")

The axis of symmetry passes through the vertex so it has the x value as the vertex.

color(green)("Axis of symmetry "-> x=3)

Tony BTony B