Question

Which is the domain and range of the parabola with the equation y = 0.5(x2 – 8x – 6)?

D: (–∞, ∞); R: (–∞, –11]
D: (–∞, ∞); R: [–11, ∞)
D: (–∞, –11]; R: (–∞, ∞)
D: [–11, ∞); R: (–∞, ∞)

Answer 1

Answer:

D: (–∞, ∞); R: [–11, ∞)

Step-by-step explanation:

The domain of a quadratic function is all real numbers, so eliminate the third and fourth options.

Also, since the coefficient of $x^2$ is positive, we know the graph opens up and thus has a minimum.

This means that the first option must be wrong since the range has a maximum, not a minimum.

Therefore, the correct answer is Option 2.