Hello everyone, this is my first post in the Math Help Forum. I was wanting to know if anybody out there can prove that x = 3 (without just 'plugging it' in) in this equation that my friend made:

^{3}√(8x+3) -^{3}√(x-4) = 4 (third roots)

Here's what I have of the proof so far: View image: Proof of the Super Equation( WIP) Sorry if you can't follow it lol...

What would you recommend I do as the next step? The numbers are really getting out of control...