It doesn’t always have to be complicated, math, to be fun.
Take a number, add two to it, multiplicate these two, ad one to the stew, and you have the quadratic tern of the average of the first two numbers.
Let’s do another.
The solution is simple. Let the first number be , the second and you get
You could also use another binomial when is considered to be the average
Math always works out correct. Never surprises. Phew.