That is not factual.
I didn't say that the right answer wasn't posted. I said the correct solution hadn't been posted yet.
The solution you propose is longer and requires more work.
This solution uses the defining properties of both ellipse and hyperbola. This is shorter.
It can be shortened more because you don't even need to know. He could've got that with EM. It is obvious that solving 2 linear equations is terse and therefore best.
@bobbym, it is amazing that you didn't get the right answer for 8. Your diagram shows you were working on the wrong hyperbola!
The red one is the right hypie.
The correct solution is not yet given so I'll put it down.
This solution uses the defining properties of both ellipse and hyperbola.