The domain of increase is x = 4 to x = 10
When we talk of the domain on which the function is increasing, we simply refer to the values of x for which there is a rise in the value of y
This will start from the point where the graph touches the x-axis
From this point upwards, we have the domain we are looking for
From the image of the question, this domain is ;
We can see that the graph was decreasing until it took a sharp turn at x = 4
So the domain of increase is x = 4 to 10