determine the intervals in which the graph is increasing

Determine the intervals where the graph increases.

I don't know how to draw a graph here or if it is possible.

I think that the answer is B, but I'm not really sure.

Solution 1:

Hint:

The graph is increasing at a point $x$ if the function values of points smaller than $x$ are also smaller than $f(x)$, and function values of points larger than $x$ are larger than $f(x)$.

Looking at the graph, that means that for a given number $x$, you look at the point $P=(x,f(x))$ on the graph. The function is increasing if the points to the left of $P$ are below $P$ and points to the right of $P$ are above it.

Solution 2:

The answer is C) $[-1,1]$. The function is said to be increasing if $x\geq y\implies f(x)\geq f(y)$. So for the portion between $x=-1$ and $x=1$ the function value is increasing as depicted on the graph.