Question

Which intervals show f(x) decreasing? Check all that apply. [–2.5, –2] [–2, –1.5] [–1, 1) [1.5, 2] [2, 2.5) (2.5, 3]

Answer 1

A function f is increasing on an interval if for every x1, x2; x1  x2, f(x1)  f(x2). A function f is decreasing on an interval.

If for every x1, x2; x1  x2, f(x2)  f(x1).

So, here for intervals  [–2.5, –2] and [1.5, 2] f(x) is increasing while for [–2, –1.5] and [2, 2.5] it is decreasing.