The demand function of a company's product is:

The current demand is 3000 units.
What price will maximize revenues? What will be the demand at this price?
I've tried everything that I could to try and solve it but I can't seem to do it. I'll show everything that I've done so far.

<---- used implicit differentiation

<------ equation for elasticity

<----- set E =1 to try and solve for maximum revenue

<--- try and solve for p
I keep getting p = 0 but that doesn't really make any sense at all. When I tried to solve it in terms of x, I kept on getting 0 = 3000.
Please help me, I promise i'll rate as high as possible!