Rico is asked to graph a parabola given the equation y=−x2−2x . At which point would he graph the vertex of the parabola?(1 point)

Responses

(−1,2)
left parenthesis negative 1 comma 2 right parenthesis

(1,2)
left parenthesis 1 comma 2 right parenthesis

(−1,0)
left parenthesis negative 1 comma 0 right parenthesis

(−1,1)
left parenthesis negative 1 comma 1 right parenthesis

1 answer

To find the vertex of the parabola given by the equation \( y = -x^2 - 2x \), we can rewrite the equation in vertex form or use the standard vertex formula.

The standard form of a quadratic equation is \( y = ax^2 + bx + c \). In this case, \( a = -1 \) and \( b = -2 \).

The x-coordinate of the vertex \( x_v \) can be found using the formula:

\[ x_v = -\frac{b}{2a} \]

Substituting the values of \( a \) and \( b \):

\[ x_v = -\frac{-2}{2 \cdot -1} = \frac{2}{-2} = -1 \]

Now, we need to find the y-coordinate of the vertex by substituting \( x_v \) back into the original equation:

\[ y = -(-1)^2 - 2(-1) = -1 + 2 = 1 \]

Thus, the vertex of the parabola is at the point:

\[ (-1, 1) \]

So the correct response is:

(−1, 1)