 okay so substituting into the equation for xb we get and we find c equals gamma three quarters of the way there the next one's a little bit trickier so if we make the substitution we get this and dividing all sides by delta ta we get or rather e is minus one over v one on gamma minus gamma and then this is where the hint's coming so for one on gamma minus gamma we just write the second term as a fraction for one minus gamma squared we have we recognize that this is equal to okay so substituting these values into our expression for e we find e is equal to v on c squared gamma so now we have our Lorentz transformations