Hi I have a problem that I think that is simple, but I don't know how to write it in code.

Suppose that you have a function $f(x)=l_{0}x^{2}$ and you want to plot it as a function of $x$ In the interval $x\in[0,10]$. I Know that i can do it as

Plot[Evaluate[f(x)], {x,  0 , 10, PlotRange -> All]

But the problem is that i have another function that depends of $l_{0}$, and I want to plot in the same graph, but the $x$-axis can't be used anymore. However, I have seen in some papers link that they use some kind of density plot, but i don't know how to do it, can you help me?