They mean: to make the quadratic equation easy to remember.
However, I don't think this will have any impact on the average high school student.
The key is:
> Loh points out that the two roots, R and S, add up to -B when their average is -B/2.
> “So we seek two numbers of the form -B/2±z, where z is a single unknown quantity,” he says. We can then multiply these numbers together to get an expression for C.
But you still have to derive the formula and their first example assumes A is fixed.
Comments
They mean: to make the quadratic equation easy to remember.
However, I don't think this will have any impact on the average high school student.
The key is:
But you still have to derive the formula and their first example assumes A is fixed.
This is usually how completing the square is taught, in my experience. The leading coefficient is handled later with "just divide everything by a".