Log-log graphs are when you graph out the log values for x against the log values of y.
If you plot it and you get a linear function, then you know there is a relationship between the 2 variables that can be expressed as a function.
This doesn’t work for general polynomials like
The Proof
y = 4x^2
log(y) = log(4x^2)
logy = log(4) + log(x^2)
logy = log(4) + 2log(x)
let y represent logy
let x represent logx
y = 2x + log(4)