The red parabola shown is the graph of the equation $y=ax^2 + bx + c$. Find $a\cdot b\cdot c$.
The red parabola shown is the graph of the equation $y=ax^2 + bx + c$. Find $a\cdot b\cdot c$.
The vertex is (-3, 5)
And the x coordinate of the vertex is given by
-b / [ 2a] = -3
b = 6a
And the point (-1, 3) is on the graph.....so.....we have this system
3 = a(-1)^2 + 6a (-1) + c
5 = a(-3)^2 + 6a(-3) + c simplify
a - 6a + c = 3
9a - 18a + c = 5
-5a + c = 3
-9a + c = 5 multiply the second equation through by -1
-5a + c = 3
9a - c = -5 add these
4a = -2
a = -2/4 = -1/2
So b = 6(-1/2) = -3
And -9a + c = 5 ....so....
-9(-1/2) + c = 5
9/2 + c =10/2
c = 10/2 - 9/2 = 1/2
So
a * b * c =
(-1/2) * (-3) * 1/2 =
3 / 4
Here's a graph : https://www.desmos.com/calculator/nl6jcccb3k