Let f : R → R be defined as
\(f(x)= \begin{cases}-55 x, & \text { if } x<-5 \\ 2 x^3-3 x^2-120 x, & \text { if }-5 \leq x \leq 4 \\ 2 x^3-3 x^2-36 x-336, & \text { if } x>4\end{cases}\)
Let A = {x ∈ R ∶ f is increasing}. Then A is equal to :
1
(-5, -4) ∪ (4, ∞)
2
(-5, ∞)
3
(-∞, -5) ∪ (4, ∞)
4
(-∞, -5) ∪ (-4, ∞)
5
Question Not Attempted