Question

How many roots does `y=x^2-2x+1` have?

Answer 1

This quadratic has two zeros counting multiplicity, but they coincide. So there is only one value of `x` for which `y = 0`

Explanation:

`y = x^2-2x+1 = (x-1)(x-1)`

So this quadratic in `x` has one zero of multiplicity `2`, namely `x=1`.

Alternatively, you could say that `x^2-2x+1=0` has exactly two roots, counting multiplicity.