# How to expand this polynomial division?

My Physics teacher gave me a problem and its solution, what I have todo is to expand the solution, but when I do it I do not get to the same solution he says is the right one, here is the problem:

We cut off a rectangle ABCD along the line DE through the corner D, so when we suspend the plate ABED from the point E the line DA, is on horizontal position. Calculate the magnitude EB

The image below is the solution, What I am not able to figure out is how the teacher solved the polynomial division and get to that result.

Any help is appreciated

• Try multiplying each term in the numerator and denominator by $6/h$, then simplifying the denominator. – N. F. Taussig Sep 7 '14 at 20:03
• @N.F.Taussig Another question, how did you know that? – Victor Castillo Torres Sep 7 '14 at 20:20
• @N.F.Taussig How, did you get to that? please answer – Victor Castillo Torres Sep 7 '14 at 21:37