Answer :
It's pretty simple actually, since it's almost completely solved.
4x^2-1=8x (move the 8 to the opposite side)
4x^2-1-8x (now rearrange the order)
4x^2-8x-1 done!
4x^2-1=8x (move the 8 to the opposite side)
4x^2-1-8x (now rearrange the order)
4x^2-8x-1 done!