SOLUTION: I am trying to find the vertex for the function: f(x)=x^2 + x - 2. I believe the axis of symmetry is -1/2 since x= -b/2(a)(which should be the x-coordinate) but when I plug it in t

Question 151429: I am trying to find the vertex for the function: f(x)=x^2 + x - 2. I believe the axis of symmetry is -1/2 since x= -b/2(a)(which should be the x-coordinate) but when I plug it in to find y I am coming up with - 3/2 which doesnt seem correct. Where am i going wrong, and what would be the vertex?
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!

In order to find the vertex, we first need to find the x-coordinate of the vertex.

To find the x-coordinate of the vertex, use this formula: .

Start with the given formula.

From , we can see that , , and .

Plug in and .

Multiply 2 and to get .

So the x-coordinate of the vertex is . Note: this means that the axis of symmetry is also .

Now that we know the x-coordinate of the vertex, we can use it to find the y-coordinate of the vertex.

Start with the given equation.

Plug in .

Square to get .

Multiply by to get .

Multiply by to get .

Combine the fractions.

So the y-coordinate of the vertex is .

So the vertex is

in decimal form.

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