SOLUTION: Find the verex and intercepts. Sketch the graph g(x) = x^2 + -6

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Question 147135: Find the verex and intercepts. Sketch the graph
g(x) = x^2 + -6

Found 3 solutions by edjones, checkley77, Edwin McCravy:
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
The y intercept is -6
.
x^2-6=0
x^2=6
x=-sqrt(6), x=sqrt(6) the x intercepts.
.
The vertex at x=sqrt(6)-sqrt(6)=0
The vertex at y=-6 special case.
.
graph%28500%2C500%2C-10%2C10%2C-10%2C10%2Cx%5E2-6%29
.
Ed

Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
g(x) = x^2 + -6
+graph%28+300%2C+200%2C+-6%2C+5%2C+-10%2C+10%2C+x%5E2+-6%29+ (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, x^2 -6).
Vertex=-6
Y Intercept=-6
X Intercepts=+-2.5

Answer by Edwin McCravy(20077) About Me  (Show Source):
You can put this solution on YOUR website!
Edwin's solution:
Find the verex and intercepts. Sketch the graph
g%28x%29+=+x%5E2+-6

The vertex formula:

The graph of 

f%28x%29+=+ax%5E2%2Bbx%2Bc

has the vertex (-b%2F%282a%29, -d%2F%284a%29), where d+=+discriminant+=+b%5E2-4ac

Therefore
g%28x%29+=+x%5E2+-6

can be written as

g%28x%29+=+x%5E2%2B0x-6

So we apply the vertex formula:

a=1, b=0, c=-6, d=discriminant=b%5E2-4ac=0%5E2-4%281%29%28-6%29=24

so the vertex is

(-b%2F%282a%29, -d%2F%284a%29) =

(-0%2F%282%281%29%29, -24%2F%284%281%29%29) = (0%29, -6)

To find the y-intercept, we substitute x=0

g%28x%29=+x%5E2+-6

g%280%29+=+0%5E2+-6

So the y-intecept is (0, -6), which just happens
to, in this case, be the same point as the vertex.

To find the x-intercepts, we we substitute g%28x%29=0

g%28x%29=+x%5E2+-6
0=+x%5E2+-6
-x%5E2=-6
x%5E2=6
x = ±sqrt%286%29
 
Since the square root of 6 is about 2.45,

the two x intercepts are about (-2.45, 0) and (2.45, 0)

So we plot those two points, as well as:

vertex: (0%29, -6)

and

y-intercept: (0%29, -6) [Which in this case just 
happens to be the same point as the vertex.]



Edwin