Change label dynamically

[intelaravind]

I have a graph with 5 lines. The scale of each line is very different (and the scale varies for different users). Hence I want to allow the user to scale the data (using a slider). This part works perfectly, and I am able to update the values. However, now I want my label to be changed, so that it reflects the scale. For eg: if original label was "frequency", and it was scaled by 2, I want the label to be "frequency * 2". How can I do the same?