Answer
a) secant
b) 3
Work Step by Step
a) The average rate of change of a function f between x=a and x=b is the slope of the secant line between (a, f(a)) and (b, f(b)).
b) The average rate of change of the linear function f(x)=3x+5 between any two points is 3. The function 3x+5 represents a line with the slope m=3 so the slope of the secant line between any two points is constant m=3.
