SOLUTION: Algebra 1 chapter 9 Resource Book lesson 9.3 Practice A I am having dificulty trying to figure out the coordinates to a problem that contains an a, b, c and even more when b and

Algebra ->  Algebra  -> Quadratic Equations and Parabolas -> SOLUTION: Algebra 1 chapter 9 Resource Book lesson 9.3 Practice A I am having dificulty trying to figure out the coordinates to a problem that contains an a, b, c and even more when b and      Log On

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Question 115642: Algebra 1 chapter 9 Resource Book lesson 9.3 Practice A
I am having dificulty trying to figure out the coordinates to a problem that contains an a, b, c and even more when b and c are sometimes missing.
Find the coordinates of the vertex.
1. y= 3x²
2. y= 5x²-1
3. y= x²+6x

Answer by vertciel(183) About Me  (Show Source):
You can put this solution on YOUR website!
Hello there,
When b and c are missing, their value is 0 because they're missing!
1. The vertex is at (0,0).
There are two ways to find this out:
1) For the graph y = x^2, the vertex is at (0,0). The equation y = 3x^2 means that y = x^2 is stretched out, so the vertex hasn't changed.
2) You can use the formula +h+=+-b%2F2a.+
h = -b/2a
= 0/2(3)
= 0
Plug 0 into the equation of the parabola:
l = f(0) = 0^2
= 0

2. y = 5x^2 - 1
h = -b/2a
= -0/2(5)
= 0
k = f(0) = 5(0)^2 - 1
= -1
Therefore, the vertex is at (0, -1).
Try to do #3 on your own. Please write back if you need more help!