You bought 3/4 pound of dry ice for an experiment when the experiment was over you found that you had used only one third of what you bought how much dry ice did you use

The total number of photos on hannah’s camera is a linear function of how long she was in rome. she already had 44 photos on her camera when she arrived. then she took 24 photos each day for 6 days. what is the rate of change of the linear function that represents this

How to do this , and can some one explain

What does the sign of the slope tell you about a line?