Question

Must a function that is decreasing over a given interval always be negative over that same interval? Explain.

Answer 1

For a function to be decreasing over an interval, the outputs on the function are getting smaller as the inputs of the function are getting larger, but the outputs could be positive or negative. For a function to be negative over an interval, the outputs must be negative, while the inputs could be positive or negative.

Answer 2

It doesn't have to be. a negatively sloped line could start at (2,3) and end at (5,-3) and decrease. The function is still decreasing however, the y value doesn't have to be negative