Join IDNLearn.com to access a wealth of knowledge and get your questions answered by experts. Our platform provides prompt, accurate answers from experts ready to assist you with any question you may have.

The temperature in Vancouver was recorded over a period of four hours. The equation
[tex]\[ y = -2x + 43 \][/tex]
describes the temperature over this time, where [tex]\( y \)[/tex] is the temperature in degrees Fahrenheit ( [tex]\(^{\circ}F \)[/tex] ) and [tex]\( x \)[/tex] is the number of hours since measurements started. Which of the following statements correctly describes the temperature?

A. It was [tex]\( -2^{\circ} F \)[/tex] after four hours, and it is rising by 43 degrees per hour.
B. It was [tex]\( 43^{\circ} F \)[/tex] after four hours, and it is dropping by 2 degrees per hour.
C. It was [tex]\( 43^{\circ} F \)[/tex] when the temperature was first measured, and it is dropping by 2 degrees per hour.
D. It was [tex]\( -2^{\circ} F \)[/tex] when the temperature was first measured, and it is rising by 43 degrees per hour.


Sagot :

To determine which statement correctly describes the temperature, we need to analyze the given equation:
[tex]\[ y = -2x + 43 \][/tex]

In this equation:
- [tex]\( y \)[/tex] is the temperature in degrees Fahrenheit ([tex]\( F \)[/tex]).
- [tex]\( x \)[/tex] is the number of hours since the measurements started.

Starting with the key points of the equation:

1. Initial Temperature:
- When the temperature was first measured, [tex]\( x = 0 \)[/tex].
- Substitute [tex]\( x = 0 \)[/tex] into the equation:
[tex]\[ y = -2(0) + 43 \][/tex]
[tex]\[ y = 43 \][/tex]
- Therefore, the initial temperature when the measurements started was [tex]\( 43^\circ F \)[/tex].

2. Rate of Temperature Change:
- The coefficient of [tex]\( x \)[/tex] in the equation, which is [tex]\(-2\)[/tex], represents the rate of temperature change.
- A negative coefficient indicates that the temperature is decreasing.
- Specifically, the temperature is dropping by [tex]\( 2^\circ F \)[/tex] per hour.

Now, let's examine each of the given statements:

A. It was [tex]\(-2^\circ F\)[/tex] after four hours, and it is rising by 43 degrees per hour:
- Incorrect. The initial temperature is [tex]\( 43^\circ F \)[/tex] and it is dropping, not rising.

B. It was [tex]\( 43^\circ F \)[/tex] after four hours, and it is dropping by 2 degrees per hour:
- Incorrect. The temperature was [tex]\( 43^\circ F \)[/tex] initially (at time [tex]\( x = 0 \)[/tex]), not after four hours.

C. It was [tex]\( 43^\circ F \)[/tex] when the temperature was first measured, and it is dropping by 2 degrees per hour:
- Correct. This statement accurately reflects that the initial temperature was [tex]\( 43^\circ F \)[/tex] at the start of the measurements and that it is decreasing by [tex]\( 2^\circ F \)[/tex] each hour.

D. It was [tex]\(-2^\circ F\)[/tex] when the temperature was first measured, and it is rising by 43 degrees per hour:
- Incorrect. The initial temperature was [tex]\( 43^\circ F \)[/tex] and the temperature is dropping, not rising.

Therefore, the correct statement is (C): "It was [tex]\( 43^\circ F \)[/tex] when the temperature was first measured, and it is dropping by 2 degrees per hour."
Thank you for using this platform to share and learn. Keep asking and answering. We appreciate every contribution you make. For dependable answers, trust IDNLearn.com. Thank you for visiting, and we look forward to helping you again soon.