"c" is easy.... it's = 7
The vertex is at (h, k) = (-1, 8) and the point (2. -1) is on the graph
So we have
y = a(x - h)^2 + k
-1 =a(2- (-1))^2 + 8
-1 = a(3)^2 + 8 subtract 8 from both sides
-9 = a(9) divide both sides by 9
-1 = a
And the x coordinate of the vertex is given by -b/2a
So we have
-1 = -b/2(-1) → -1 = -b/-2 → b = - 2
So.....our function is
y = -1x^2 - 2x + 7
So
a + b + 2c =
-1 + (-2) + 2(7) =
11
"c" is easy.... it's = 7
The vertex is at (h, k) = (-1, 8) and the point (2. -1) is on the graph
So we have
y = a(x - h)^2 + k
-1 =a(2- (-1))^2 + 8
-1 = a(3)^2 + 8 subtract 8 from both sides
-9 = a(9) divide both sides by 9
-1 = a
And the x coordinate of the vertex is given by -b/2a
So we have
-1 = -b/2(-1) → -1 = -b/-2 → b = - 2
So.....our function is
y = -1x^2 - 2x + 7
So
a + b + 2c =
-1 + (-2) + 2(7) =
11