Question

pretest: quadratic relationships
which of the following statements is true for this situation?
a. the material’s temperature reaches a minimum at 15 hours.
b. the material’s initial temperature is -30 degrees celsius
c. the material’s temperature reaches a maximum at 25 hours.
d. the material returned to its initial temperature after 40 hours.

Explanation:

Step1: Analyze Option A

The graph is a parabola opening upwards, so it has a minimum. The vertex (minimum point) seems to be around x = 20 (not 15), so A is false.

Step2: Analyze Option B

Initial temperature is at x = 0. From the graph, at x = 0, the y - value (temperature) is - 30 (since it's on the - 30 mark on the y - axis), so check if this is correct.

Step3: Analyze Option C

The parabola opens upwards, so it has a minimum, not a maximum. So C is false.

Step4: Analyze Option D

Initial temperature at x = 0 is - 30. At x = 40, the y - value is much higher (positive), not - 30, so D is false.

Answer:

B. The material’s initial temperature is - 30 degrees Celsius