Question

What is the vertex of the graph of y = x2 + 4x?

(–2, –12)
(–2, –8)
(–2, –6)
(–2, –4)

Answer 1

the answer is (-2,-4)

Answer 2

(-2, -4)

Explanation:

Let's remember how to calculate the vertex of a parabola:

If we have the equation of the parabola given in the form y = ax^2 + bx + c, the x-coordinate of the vertex is x = -b/2a. For the y-coordinate we just replace the x of the equation with -b/2a and do the calculation.

In this case, a = 1, b = 4, c = 0.

The x-coordinate of the vertex is x = -4/2*1 = -2

The y-coordinate is y = (-2) ^2 + 4*(-2) = 4 - 8 = -4

Therefore, the vertex is (-2, -4)