SOLUTION: This problem is a porabola equation. i really need help. The question is, : (A.) tell whether the graph opens up or down. (b) find the coordinatnts of the vertex. (c) Write an eqq

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: This problem is a porabola equation. i really need help. The question is, : (A.) tell whether the graph opens up or down. (b) find the coordinatnts of the vertex. (c) Write an eqq      Log On


   



Question 448426: This problem is a porabola equation. i really need help.
The question is, : (A.) tell whether the graph opens up or down. (b) find the coordinatnts of the vertex. (c) Write an eqquation of the axis of symmetry.(D) Find the roots of the equation. and graph the function. The equation is: 2x^2-4x-16=y

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 
Hi
y= 2x^2-4x -16
Note: the vertex form of a parabola, y=a%28x-h%29%5E2+%2Bk where(h,k) is the vertex
y= 2x^2-4x -16 |Completing the square
y = 2[(x-1)^2 - 1] -16
y = 2(x-1)^2 - 2 -16
y = 2(x-1)^2 -18 Vertex(1,-18) a = 2 > 0 parabola opens upward
Line of symmetry is x = 1
x-intercepts when y = 0 are also the solutions for the quadratic equation
2(x-1)^2 = 18
x-1 = ± sqrt%289%29
x = 1 ± 3 x = 4 or x = -2