Answer
a) nowhere
b) $\left( -4,2 \right)$.
c) $\left( -\infty ,-4 \right)\cup \left( 2,\infty \right)$.
Work Step by Step
(a)
The function is said to be increasing in an interval when the value of y increases as the value of x increases. Hence, the given function is increasing nowhere.
(b)
The function is said to be decreasing in an interval when the value of y decreases as the value of x increases. Hence, the given function is decreasing on the interval $\left( -4,2 \right)$.
(c)
The function is said to be constant in an interval when the value of y remains same as the value of x increases.
Hence, the given function is constant on the interval $\left( -\infty ,-4 \right)\cup \left( 2,\infty \right)$.