Answer:
See attached graph
Step-by-step explanation:
Let m be the number of minutes passed and T be the temperature (in F°)
Before the window is opened, the temperature was 70°F, then at m = 0 minutes, T = 70°F
When a window is open, the temperature in a room falls 5°F every 15 minutes. This means
at m = 15, T = 70°F - 5°F = 65°F
at m = 30, T = 70°F - 10°F = 60°F
at m = 45, T = 70°F - 15°F = 55°F
and so on.
Plot points (0,70), (15,65), (30, 60), (45, 55) and connect them with a straight line. This is the graph that shows the temperature of the room, T, after the window has been open for m minutes.