Instead of solving for h and then dividing e by that h, you could divide both sides by e to get and solve it to find . This can also be done starting from the initial equation . If we denote e / h by x, then the equation becomes , which turns into a quadratic equation in x after multiplying by x.
When I was in a freshman in high school, I took part in a math competition designed for sophomores. There was a quadratic equation, and I could not solve it because we had not covered the quadratic formula yet though I believe we had covered completing the square. Later my math teacher told me that I could have derived the quadratic formula by completing the square. So don't be afraid to study the quadratic formula and how to derive it. I personally never use factorization but instead apply the quadratic formula.