calculus
posted by bobbie .
Given the function f(x) = 3x  9
a. Find the rate of change between the two stated values for x: 7 to 8
b. Find the equation of a secant line containing the given points: (7, f(7)) and (8, f(8))

curious question in Calculus.
Since the function is a straight line, it seems very odd to be talking about secant lines, anyway ....
f(7) = 12
f(8) = 15
rate of change = (1512)/(87) = 3
Note that this is the slope of the given line as expected.
The equation of the secant line would of course be the line itself , or f(x) = 3x9