SOLUTION: Given y=9x^2-6x+3, What is the equation of the axis of symmetry? a)x=2/3 b)x=-1/3 c)x=-2/3 d)x=1/3 what are the coordinates of the vertex? Y-intercepts: X-intercepts:

Algebra ->  Rational-functions -> SOLUTION: Given y=9x^2-6x+3, What is the equation of the axis of symmetry? a)x=2/3 b)x=-1/3 c)x=-2/3 d)x=1/3 what are the coordinates of the vertex? Y-intercepts: X-intercepts:       Log On


   



Question 138225: Given y=9x^2-6x+3,
What is the equation of the axis of symmetry? a)x=2/3 b)x=-1/3 c)x=-2/3 d)x=1/3
what are the coordinates of the vertex?
Y-intercepts:
X-intercepts:
I think it opens up, but that is as far as i got...
I appreciate any help! Thank you!

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!
Given ax%5E2%2Bbx%2Bc, the x-coordinate of the vertex of the parabola is given by %28-b%29%2F2a, hence the axis of symmetry is x=%28-b%29%2F2a. The y-coordinate of the vertex is the value of the function at the x-coordinate of the vertex. So the vertex is at (%28-b%29%2F2a,f%28%28-b%29%2F2a%29)

The x-intercepts are the values of x that make the function = 0, so set your function equal to 0 and solve the quadratic equation. If you end up with real roots, the x-intercepts are (x1,0) and (x2,0). If you end up with a conjugate pair of complex roots, then there are no x-intercepts.

The y-intercept is the value of the function at 0, so substitute 0 for x and do the arithmetic. The y intercept is (0,f(0))

And you are right, it does open up. A parabola opens upward whenever a%3E0, and downward when a%3C0