SOLUTION: Please help me solve this. For the following function determine the values of x for which f is (a) an increasing function (b) a decreasing function (c) constant f(x) = (4x+20)

Algebra ->  Linear-equations -> SOLUTION: Please help me solve this. For the following function determine the values of x for which f is (a) an increasing function (b) a decreasing function (c) constant f(x) = (4x+20)      Log On


   



Question 973960: Please help me solve this.
For the following function determine the values of x for which f is (a) an increasing function (b) a decreasing function (c) constant
f(x) = (4x+20)^9
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4

f'(x) = 9((4x+20)^8)

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
(4x+20)^9
when x= -5, the function is 0. When x= -4.75 the function is 1. Those are constants
When x < -5 it is decreasing.
When x >-5 it is increasing.
The derivative is 9(4x+20)^8 *4, which equals 0 when x=-5