Lesson 2

The temperature for a city is a function of time after midnight. The graph shows the values on a particular spring day.

1. What does the point on the graph where \(x = 15\) mean?
2. What is the temperature at 5 p.m.?
3. What is the hottest it gets on this day?
4. What is the coldest it gets on this day?

For each of these equations, find the value of \(y\) when \(x = \text{-}2\).

1. \(y = 3x - 4\)
2. \(y = 10 - 2x\)
3. \(y = \frac{3}{2}x + 5\)
4. \(y = 2(x - 1) + 4\)
5. \(y = \text{-}x + 19\)
6. \(y = \frac{x - 3}{8}\)
7. \(y = 0.3x + 5\)

The temperature, in degrees Fahrenheit, of a scientific sample being warmed steadily as a function of time in seconds after the sample is put in a machine can be represented by the equation \(y = 2.1x + 86\).

1. What does it mean when \(x = 2\)?
2. What is the temperature in that situation?
3. What does it mean when \(y = 122\)?
4. A graph of this equation goes through the point \((60,212)\). What does that mean?
5. Give 2 values for \(x\) that do not make sense. Explain your reasoning.
6. Give 2 values for \(y\) that do not make sense. Explain your reasoning.