Question

.Find the vertex of the parabola whose equation is y = x2 + 2x + 9.

(-1, 8)

(1, 12)

(0, 9)

Answer 1

The vertex of the parabola is the point where the axis and parabola intersect. Its
x-coordinate \(x=-\dfrac{b}{2a}\) is its y-coordinate is found by substituting
\(x=\frac{-b}{2a}\) in the parabola’s equation.

Answer 2

So, compare your given eqn to the quadratic expression \(ax^2 + bx + c \) and you find

\(a = 1, b=2, c=9\)

x-coordinate of vertex = \(\dfrac{-2}{2*1} = -1\)

y-coordinate of vertex = \(\small (-1)^2 + 2(-1) + 9 = 1 -2 + 9\rightarrow 8\)

Vertex: (-1, 8)

Answer 3

thank you again d3Xter! :)

Answer 4

np :)