Question

khloe is preheating her oven before using it to bake. khloe wants to predict the final temperature after x minutes. she wrote the equation y = 20x + 78, where y represents the final temperature in degrees fahrenheit. what is the meaning of the y-value when x = 1?

answer

the oven’s temperature after 0 minutes.
the time when the oven’s temperature is 0°.
the rate of change in the oven’s temperature over time.
the oven’s temperature after 1 minute.

Explanation:

In the equation \( y = 20x + 78 \), \( x \) represents the number of minutes and \( y \) represents the oven's temperature. When \( x = 1 \), we are finding the value of \( y \) (temperature) after 1 minute. Let's analyze each option:

• "The oven’s temperature after 0 minutes" would be when \( x = 0 \), not \( x = 1 \), so this is incorrect.
• "The time when the oven’s temperature is \( 0^\circ \)" would involve solving \( 0 = 20x + 78 \) for \( x \), not evaluating at \( x = 1 \), so this is incorrect.
• "The rate of change in the oven’s temperature over time" is the slope (20) of the equation, not the value of \( y \) when \( x = 1 \), so this is incorrect.
• "The oven’s temperature after 1 minute" matches the interpretation of \( x = 1 \) (1 minute) and \( y \) being the temperature at that time.

Answer:

The oven’s temperature after 1 minute.