Step-by-step explanation:
f(1) = 3×1 - 1 = 2
f(4) = 3×4 - 1 = 12-1 = 11
so, the functional value changes 11-2=9 units on an x interval of 4-1=3 units length.
the average change rate is the total change across the x interval relative to the interval length.
that is
9/3 = 3
which is the slope (= the factor of x) in the line equation.
for a line its change rate for any point is the same constant. and that is therefore automatically also the average change rate across an interval of x values.
if the change rate would be different for different parts of the function, it would not be a straight line.
Answer:
3
Step-by-step explanation:
The average rate of f(x) in the closed interval [ a, b ] is
[tex]\frac{f(b)-f(a)}{b-a}[/tex]
Here [ a, b ] = [ 1, 4 ] , then
f(b) = f(4) = 3(4) - 1 = 12 - 1 = 11
f(a) = f(1) = 3(1) - 1 = 3 - 1 = 2
average rate of change = [tex]\frac{11-2}{4-1}[/tex] = [tex]\frac{9}{3}[/tex] = 3
