what is the equation of the following graph

Question

anonymous · Answer

http://roads.advancedacademics.com/contentserver/content/roadssection/279670/questions/assessments/l-determiningquadraticfunctionquiz/a2_1.7_quiz_15.bmp

anonymous · Answer

@Directrix

primeralph · Answer

We all do.

anonymous · Answer

hehe ok back to math direct i got a =-1

primeralph · Answer

First, start with the intercepts. What are they?

anonymous · Answer

the vertex is 5,1

anonymous · Answer

intercepts are 4 and 6

primeralph · Answer

That's really all you need.
(x-4)(x-6)

anonymous · Answer

A.	f(x) = x2 + 10x - 24
	B.	f(x) = -x2 + 10x - 24
	C.	f(x) = x2 - 10x + 24
	D.	f(x) = -x2 + 10x + 24

anonymous · Answer

ohh ok i get it

anonymous · Answer

i ll multiply that and get my awnser

primeralph · Answer

Yeah.

anonymous · Answer

wow man my school is like showing me this weird stuff makes my head hurt made it seems soo hard

anonymous · Answer

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primeralph · Answer

Well, sometimes the intercept isn't easy to spot on the graph, so that's when you use the vertex method. It's good to know both.

anonymous · Answer

vertex method its the y=a(x+h)+2 right?

primeralph · Answer

No. That's a straight line. This is a curve. The vertex is at x = -b/(2a).
So in this case, 5 = -b/(2a)
10a = -b    is your first equation
Plug in the vertex coordinates into standard quadratic equation:
1 = a(5^2) + b (5) + c
1 = 25a +5b + c   is your second equation
Using the intercept, you can find the third equation and solve all three for a, b, c.

primeralph · Answer

It's not as hard as it looks.

anonymous · Answer

Wow thanks ralph

primeralph · Answer

You're welcome.