Pre-Video Questions

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Before watching the videos, think about and answer these questions to the best of your ability.

Melissa is driving along a straight road from Dallas, Texas to Oklahoma City, Oklahoma at a constant velocity. Every increase of ten minutes in the number of minutes $x$ since passing the state line, her distance $y$ from Oklahoma City decreases by seven miles. Which of the following statements is definitely true? (Note: $\Delta y$ can be read as “change in $y$ ” and $\Delta x$ as “change in $x$ .”)

(a) $\Delta y = -0.7 \Delta x$ (b) $y = -0.7 x$ (c) $x = -0.7 y$ (d) $\Delta x = -0.7 \Delta y$ Only statements (a) and (b) are definitely true. Only statements (c) and (d) are definitely true.

A candle has been burning at a constant rate of change of 1.25 inches per hour. The candle has been burning for 4 hours and is 5.5 inches tall. What was the length of the candle before it was lit?

5 inches 5.5 inches 6.75 inches 10.5 inches 23.25 inches

Overall, how confident are you in your answers?

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